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Ronald Reagan Presidential Library
Digital Library Collections
This is a PDF of a folder from our textual collections.
Collection: Matlock, Jack F, Jr: Files
Folder Title: Treaties & Agreements - USSR
(12)
Box: 38
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WITHDRAWAL SHEET
Ronald Reagan Library
Collection Name MATLOCK, JACK: FILES
Withdrawer
JET 5/27/2005
File Folder
USSR-TREATIES/AGREEMENT 12/24 [COOPERATION
FOIA
BETWEEN US NATIONAL BUREAU OF STANDARDS
F06-114/11
AND ACADEMY OF SCIENCES OF THE USSR]
Box Number
38
YARHI-MILO
3802
ID Doc Type
Document Description
No of Doc Date Restrictions
Doggo
12279 MEMO
KIMMITT TO HILL RE RENEWAL OF THE
1 1/26/1984 B1
MEMORANDUM OF COOPERATION
BETWEEN THE US NATIONAL BUREAU OF
STANDARDS AND THE ACADEMY OF
SCIENCES OF THE USSR
R
4/14/2011
F2006-114/11
12280 MEMO
MATLOCK TO MCFARLANE RE RENEWAL
1 1/23/1984 B1
OF MEMORANDUM OF COOPERATION
BETWEEN NBS AND USSR ACADEMY OF
SCIENCES
R
4/14/2011
F2006-114/11
12282 MEMO
HILL TO MCFARLANE RE RENEWAL OF
3 1/5/1984 B1
MEMORANDUM OF COOPERATION
BETWEEN THE US NATIONAL BUREAU OF
STANDARDS AND ACADEMY OF SCIENCES
OF THE USSR
R 4/14/2011 F2006-114/11
12283 REPORT
EUR/IG REPORT ON THE EXTENSION OF
3
ND
B1
THE MEMORADUM OF COOPERATION
BETWEEN THE US NATIONAL BUREAU OF
STANDARDS AND THE USSR ACADEMY OF
SCIENCES
R
4/14/2011
F2006-114/11
12281 MEMO
BRADY TO MORTON RE NATIONAL
5 11/16/1983 B1
BUREAU OF STANDARDS AND USSR
ACADEMY OF SCIENCES
R
4/14/2011
F2006-114/11
Freedom of Information Act - [5 U.S.C. 552(b)]
B-1 National security classified information [(b)(1) of the FOIA]
B-2 Release would disclose internal personnel rules and practices of an agency [(b)(2) of the FOIA]
B-3 Release would violate a Federal statute [(b)(3) of the FOIA]
B-4 Release would disclose trade secrets or confidential or financial Information [(b)(4) of the FOIA]
B-6 Release would constitute a clearly unwarranted Invasion of personel privacy [(b)(6) of the FOIA]
B-7 Release would disclose Information complied for law enforcement purposes [(b)(7) of the FOIA]
B-8 Release would disclose Information concerning the regulation of financial Institutions [(b)(8) of the FOIA]
B-9 Release would disclose geological or geophysical Information concerning wells [(b)(9) of the FOIA]
C. Closed In accordance with restrictions contained In donor's deed of gift.
0111 12279
I
NATIONAL SECURITY COUNCIL
WASHINGTON, D.C. 20506
January 26, 1984
CONFIDENTIAL
MEMORANDUM FOR MR. CHARLES HILL
Executive Secretary
Department of State
SUBJECT:
Renewal of the Memorandum of Cooperation between
the US National Bureau of Standards and the
Academy of Sciences of the USSR (C)
The recommendation that we propose to the Soviets the extension
of the Memorandum of Cooperation between the U.S. National Bureau
of Standards and the USSR Academy of Sciences for five years has
been approved. (C)
Robert M. 1(mmtt
Robert M. Kimmitt
Executive Secretary
DECLASSIFIED
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BY KML NARA DATE 5/2/11
954
NSC/5-
IhodwHs.,R
uncil
LDX to C Hill
e
System #
I
They
Package # 0111
KMS
S SEEN
DISPOSITION
Bil
FM
Bob Kimmitt
K
John Poindexter
4
of
Wilma Hall
5
1
6
Bud McFarlane
m
A
Bob Kimmitt
NSC Secretariat
7
D/CDX
Situation Room
Rosie
3
alone Connection TabIT
I = Information
A = Action
R = Retain
D = Dispatch
N N- - No Further
cc: VP Meese Baker Deaver Other
COMMENTS
Should be seen by:
(Date/Time)
12280 3
0111
MEMORANDUM
NATIONAL SECURITY COUNCIL
CONFIDENTIAL
January 23, 1984
ACTION
MEMORANDUM FOR ROBERT C. MCFARLANE
FROM:
JACK MATLOCK Agm
SUBJECT:
Renewal of Memorandum of Cooperation Between
NBS and USSR Academy of Sciences
The 1978 Memorandum of Cooperation between the National Bureau of
Standards (NBS) and the USSR Academy of Sciences was to
have expired on December 12, 1983, unless it was modified or
extended by mutual agreement. Although a cleared interagency
position was not forwarded to us before the expiration date,
informal soundings with the Soviets have indicated that they will
agree to extend the memorandum, despite its formal expiration, if
we wish to do so. NBS recommends that it be extended for a
five-year period and State concurs (Tab I). The intelligence
community and OSTP believe that the agreement poses no risk of
technology loss under the conditions by which it is currently
managed. Each project is subject to interagency review from the
standpoint of technology transfer before it is approved.
Since renewal of the agreement is consistent with NSDD-75 and
supports our policy of maintaining a broad dialogue with the
Soviets, USE Y recommend that a five-year extension be approved.
JL
Don Fortier and John Lenczowski concur.
RECOMMENDATION:
That you approve the Kimmitt to Hill Memorandum at Tab II which
authorizes renewal of the NBS-USSR Academy Memorandum of
Cooperation for five years.
Approve Km
Disapprove
Attachments:
Tab I
Memorandum from State
Tab II
Memorandum to State
CONFIDENTIAL
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BY KML NARA DATE 5/2/11
0111 4
8400172
United States Department of State
12282
Washington, D.C. 20520
January 5, 1984
CONF IDENTIA
MEMORANDUM FOR MR. ROBERT C. MCFARLANE
THE WHITE HOUSE
SUBJECT: Renewal of the Memorandum of Cooperation between the
US National Bureau of Standards and the Academy of
Sciences of the USSR
The 1978 Memorandum of Cooperation between the National
Bureau of Standards and the Soviet Academy of Sciences
effectively will have expired on December 12, 1983, unless it
is modified or extended by mutual agreement of the two Sides
(the Bureau and the Academy) with the concurrence of the
Executive Agencies (the Office of Science and Technology Policy
and the USSR State Committee for Science and Technology, as
designated under the US-USSR Agreement on Cooperation in the
Fields of Science and Technology).
BACKGROUND
Official science and technology exchanges with the Soviet
Union have been cut back substantially on two occasions -- in
1980 in response to the Soviet invasion of Afghanistan and in
December 1981 when, as part of the sanctions taken against the
USSR for its actions in Poland, the President announced that
three agreements (space, energy, and science and technology)
would be allowed to lapse in 1982. Even though the NBS-Soviet
Academy Memorandum referred to the Science and Technology (S&T)
Agreement, the Department of State determined that, per the
provisions of Article VIII of the S&T Agreement, the validity
of the NBS-ASUSSR Memorandum was not effected by the
termination of the S&T Agreement. Therefore, requests to
continue activities were reviewed on a case-by-case basis
through the interagency mechanism that the U.S. Government had
established. A number of activities have been approved on the
basis that NBS acquisition of information under the program was
considered beneficial to American interests. Since the
expiration of the S&T Agreement in July 1982, consistent with
our policy (made explicit in NSDD-75) not to dismantle further
the framework of exchanges, the U.S. Government decided to
renew bilateral agreements in agriculture (1982) and atomic
energy (1983) and was negotiating the renewal of the
Transportation Agreement when the KAL incident brought these
discussions to an end.
DECLASSIFIED
CONFIDENTIAL
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NLRR F06-114/11 #12282
BY KML NARA DATE 5/2/11
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-2-
It is the assessment of the National Bureau of Standards
(NBS) that the Memorandum with the Soviet Academy has resulted
in tangible benefits to the United States and should be
extended. Based on the present system of review of all Soviet
applicants for cooperative research at NBS, the intelligence
community and the Office of Science and Technology Policy
believe that this bilateral agreement does not pose a risk of
technology loss under the conditions by which it is currently
managed.
STATE'S VIEWS
The Department concurs in the assessment by the National
Bureau of Standards that the Memorandum should be extended for
another five-year period without modification of the operative
language of the agreement. Compared with the level of
activities under the bilateral agreements in atomic energy,
environment, and health and artificial heart research, the NBS
program is fairly small in scope and funding.
Given the controls which are currently exercised over the
US-Soviet S&T exchanges, we consider that technology transfer
concerns have been and will continue to be adequately addressed
through existing procedures. All activities are subject to a
case-by-case review to minimize possible technology loss.
State notes that in proposing the extension of the
Memorandum, the USG is softening, in a sense, the practical
consequences of allowing the expiration in 1982 of the S&T
Agreement and that this could be incorrectly interpreted by the
Soviets to mean that we do not have a firm policy in regard to
scientific exchanges. However, in the case of the NBS
Memorandum, State is of the opinion that the scientific and
intelligence benefits to the United States of continuing the
activities under the Memorandum outweigh any possible Soviet
misreadings of our intentions. The renewal of the Memorandum
is in line with the policy formally enunciated in NSDD-75 in
January 1983. On political grounds, consistent with this
policy that the "U.S. should not further dismantle the
framework of exchanges," it would be in the U.S. interest to
extend the NBS-Soviet Academy Memorandum.
CONFIDENTIAL
6
CONFIDENTIAL
-3-
In terms of our overall relationship with the Soviet Union,
an extension of the Memorandum would provide us some
flexibility to adjust the tightening or relaxing of our
exchanges policy to future shifts in the political situation.
We follow this approach under other agreements where we are
continuing with certain routine exchanges, particularly in
areas relating to health, pollution control, and housing
construction.
For their part, the Soviets have indicated at senior levels
a clear interest in extending the Memorandum. Early this year,
Academy Vice President Velikhov suggested that the Academy
would be interested in an extension if NBS were.
As in our other S&T exchange programs, the activities
conducted pursuant to the Memorandum afford our visiting
American specialists with opportunities not otherwise available
to gain access to Soviet scientists and facilties and to keep
abreast of Soviet developments and efforts in basic research.
This is of clear benefit scientifically to the United States.
The framework of the Memorandum also provides opportunities for
our visiting researchers to engage in informal dialogue with
their Soviet colleagues on U.S. positions on a wide range of
topics, paramount among them the American displeasure at the
continuing repression of many Soviet scientists.
STATE'S RECOMMENDATION
State recommends that we propose to the Soviets that the
Memorandum be extended for a five-year period.
Bincking Hill
Executive Secretary
Attachments:
1. EUR/IG Report on the Extension of the Memorandum of
Cooperation between the US National Bureau of Standards
and the USSR Academy of Sciences
2. NBS Evaluation
3. Memorandum of Cooperation between the US National Bureau
of Standards and the USSR Academy of Sciences
CONF IDENTIAL
DECLASSIFIED
12283
1
NLRR #12283
BY
KML
NARA DATE 5/2/11
EUR/IG REPORT ON THE EXTENSION OF THE MEMORANDUM OF
COOPERATION BETWEEN THE US NATIONAL BUREAU OF
STANDARDS AND THE USSR ACADEMY OF SCIENCES
The 1978 Memorandum of Cooperation between the National
Bureau of Standards (NBS) and the Soviet Academy of Sciences
will expire automatically on December 12, 1983. A new
agreement extending or amending the current agreement will be
required if we are to continue cooperation in this area.
The Memorandum was signed at Moscow by NBS Director Ernest
Ambler and Academy Vice President Ye. P. Velikhov on December
13, 1978, with a period of validity of five years. The
Memorandum has the status of an implementing arrangement under
the US-USSR Agreement on Cooperation in the Fields of Science
and Technology (S&T), signed on May 24, 1972. The umbrella S&T
Agreement, along with cooperative agreements in space and
energy, were allowed to lapse in 1982 in accordance with the
President's December 1981 announcement of sanctions against the
Soviet Union in response to the imposition of martial law in
Poland. Despite the non-renewal of the S&T Agreement, it was
determined by the Department of State that activities under the
NBS-ASUSSR Memorandum should continue because NBS acquisition
of information under the program was considered beneficial to
American interests and that, as an implementing arrangement,
the Memorandum would not be legally affected by the expiration
of the umbrella agreement.
The Memorandum, which provides for collaboration in the
basic sciences between NBS and various research institutes of
the Soviet Academy, specifically mentions cooperation in the
fields of thermal physics and thermodynamics, materials
science, spectroscopy, chemistry and chemical kinetics, and
cryogenic science. There are presently five applications
pending for exchange visits under this program. The Soviet
proposals are in the fields of atomic and molecular
spectroscopy, while the NBS proposals are in chemical
thermodynamics and measurement methodology for non-ionizing
electromagnetic readiation. NBS anticipates significant
scientific benefit from the American proposals, with particular
interest in the last-mentioned because of the wide difference
between current US and USSR exposure standards in this area.
SUMMARY CONCLUSIONS AND AGENCY RECOMMENDATIONS
The National Bureau of Standards' evaluation indicates:
--The cooperative program with the Soviet Academy has
provided direct, significant scientific benefit to ongoing
projects at NBS through not only the usual collaboration with
CONFIDENTTAL
DECL: OADR
CONFIDENTIAL
-2-
Soviet scientists, but as well through first-hand study of the
details of Soviet experimental techniques not ordinarily
accessible without this bilateral program.
--With the expiration of the umbrella S&T agreement, the
NBS memorandum provides access to Soviet research facilities
not possible under the remaining official bilateral science
agreements.
--The program has progressed on a modest and selective
scale at an annual cost to NBS of from $8 to 12 thousand
annually and has yet to reach the upper exchange limits noted
in the Memorandum.
--NBS scientists have generally been provided the access to
laboratory facilities as requested in their exchange
proposals. However, in a recent case when the Soviets failed
to provide already agreed-upon arrangements and laboratory
visits, NBS notified the Academy that the applications of three
Soviet scientists to visit NBS under the Memorandum would not
be processed until an explanation was provided.
--In its appraisal of applications for exchange visits, NBS
pays particular attention to the questions of reciprocity,
mutual benefit, scientific soundness, and any potential for
significant technological loss. Subject areas are limited to
those considered to be basic rather than applied research.
Soviet applications are screened by the Committee on Exchanges
(COMEX) to obtain a thorough appraisal of any potential for
undesired technology loss.
NBS, as set forth in its report (attached), recommends that
the Memoradum be renewed without modification of the text for a
period of five years.
State recommends proposing an exchange of notes with the
Soviets providing for a five-year extension. State agrees with
NBS that there is no need to modify the existing language of
the Memorandum.
Consistent with the policy directive NSDD-75, State
believes that while we should continue to monitor the overall
level of S&T exchanges in response to soviet actions, we should
not futher dismantle the framework which now exists. As in our
CONFIDENTIAL
9
CONF IDEN IAL
-3-
other S&T exchange programs, the activities conducted pursuant
to the NBS-ASUSSR Memorandum scientifically benefit NBS
programs, afford our visiting scientists access to laboratory
facilities not otherwise available to study specialized Soviet
research techniques, and keep Americans abreast of developments
in Soviet science.
State notes, however, that in proposing the extension of
the Memorandum, the U.S. Government is softening, in a sense,
the practical consequences of allowing the expiration in 1982
of the Agreement on Cooperation in the Fields of Science and
Technology: This could be incorrectly interpreted by the
Soviets to mean that we do not have a firm policy in regard to
scientific exchanges. However, in the case of the NBS
Memorandum, State is of the opinion that the scientific and
intelligence benefits to the United States of continuing the
activities under the Memorandum outweigh any possible Soviet
misreadings of our intentions. The renewal of the Memorandum
is consistent with the policy of the USG as set forth in
NSDD-75.
The Committee on Exchanges (COMEX) recommends that the
National Bureau of Standards be permitted to extend its
Memorandum and believes that NBS has done a good job of
guarding against significant téchnology loss. COMEX will
continue to review the program proposals on a case-by-case
basis.
The Office of Science and Technology Policy (OSTP) concurs
in the NBS proposal to extend the Memorandum for five years
provided that the exchange proposals continue to be reviewed
for possible technology transfer concerns as is presently being
done.
The Arms Control and Disarmament Agency, National
Aeronautics and Space Administration, National Science
Foundation, and Department of the Interior concur in the
renewal of the Memorandum for five years.
Other agencies offered no comment.
CONFIDENTIAL
A OF
12281
2
UNITED STATES DEPARTMENT OF COMMERCE
National Bureau of Standards
10
UNITED UNITED 8
Washington, D.C. 20234
NOV 16 1983
MEMORANDUM FOR Byron Morton
Deputy Director, EUR/SOV
Department of State
From: Edward L. Brady Edward L. Brady
Associate Director for
International Affairs
SUMMARY: The National Bureau of Standards recommends that,
subject to overriding foreign policy objections, it be autho-
rized to propose to the USSR Academy of Sciences that the
current Memorandum on Cooperation (MoC) between the two insti-
tutions, now scheduled to terminate December 12, 1983, be
renewed for an additional five-year period. NBS officials
have critically reviewed the implementation of the MoC and
have concluded that NBS has acquired technical information on
work in progress in institutes of the Academy of Sciences that
would be difficult, if not impossible, to obtain by other means.
This information has been of significant benefit to the accom-
plishment of NBS scientific objectives. END SUMMARY
Background: The NBS/ASUSSR Memorandum on Cooperation, a copy of which
is attached as Attachment A,-derives from extended negotiations dating
back to a proposal originally made in 1974 by the late President of the
USSR Academy of Sciences, M. V. Keldysh. It was signed at Moscow by
Academy Vice President Ye. P. Velikhov and NBS Director Ernest Ambler
on December 13, 1978, with a period of validity of five years. It has
the status of an implementing protocol of the intergovernmental Agreement
on Cooperation in the Fields of Science and Technology, dated May 24,
1972. Despite the non-renewal, on foreign policy grounds, of this umbrella
Agreement upon its termination in 1982, it was determined by a committee
representing the Department of State and other agencies of the Executive
Branch that activities under the MoC should continue because NBS acquisi-
tion of information under the program was considered beneficial to U.S.
interests. The possibility of such continuation was allowed for in
Paragraph 2 of Article 8 of the umbrella Agreement which states that
"The termination of this Agreement shall not affect the validity of
agreements made hereunder between agencies, organizations and enterprises
of both countries." This, then, is the legal basis under which implemen-
tation of the MoC has continued to the present time.
History of Implementation of the MoC: During the past five years, the
MoC has provided NBS with an operating flexibility and broad technical
DECLASSIFIED
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BY KML NARA DATE 5/2/11
Page 2
scope hitherto unavailable in our interactions with leading institutions
and scientists of the USSR and has effectively served to promote the
acquisition of unpublished information from USSR research institutions
and the achievement of mutually desired scientific objectives, through
joint work in their own laboratories as well as in ours. Each side has
appointed its own Coordinating Council to evaluate, monitor, and guide the
joint activities and scientific progress under the MoC. The high-level
significance that the Soviet side attaches to the MoC is demonstrated by
the composition of its Coordinating Council, comprised of Academician Yu.
A. Osip'yan, Director of the USSR Institute for Solid State Physics, as
Chairman, plus eight other renowned Soviet scientists, many of whom are
directors of leading research institutes and have Academy rank. The
NBS Coordinating Council consists of the NBS Director, Ernest Ambler,
as Chairman, plus senior members of the NBS staff.
As written, the MoC permits a broad program of scientific cooperation
between NBS and research institutes of the ASUSSR and specifically mentions
the fields of thermal physics and thermodynamics, materials science, spec-
troscopy, chemistry and chemical kinetics, and cryogenic science. However,
other fields of science may be included by mutual agreement. Although the
MoC provides for an annual quota of up to 14 man-months of long-term visits
(2-6 months) by each side to the other, plus a quota of up to 6 man-months
of short-term visits by senior scientists and program managers, we have
not yet approached these upper limits in our cooperative activities.
Rather, the program has progressed on a more modest and selective scale
at an annual cost to NBS of about $8-12K for transportation and sub-
sistence. The Soviet side has preferred visits of longer duration (up to
3 months), whereas NBS scientists have concentrated on shorter visits (2
weeks to 1 month). The overall usage of the quota has been in favor of
the Soviets by a ratio of about 2 Soviet visitors to 1 NBS, but the techni-
cal benefits are judged to have been generally equal.
NBS scientists who have participated in the program have without exception
reported that Soviet willingness to cooperate at the working scientist
level in an effort to make activities scientifically valid and productive
is quite high. For example, NBS scientist Dr. Daniel Kelleher, who
returned just last month from a two-week familiarization visit to Soviet
laboratories, has reported that he encountered a number of forefront Soviet
scientific programs that had not previously been known to him and that he
had identified several areas where a joint effort would probably lead to
significant, mutual scientific payoff. He further commented that non-
renewal of the MoC would cut off a source of useful information for him.
This observation is in accord with the general view of NBS that the full
potential of benefit from the MoC has not yet been exploited.
Page 3
This is not to say, however, that the program runs entirely smoothly.
Bureaucratic and logistical problems on the Soviet side continue to
interfere with gaining the maximum possible benefit from the cooperation.
The recent one-month visit of NBS scientist Dr. J. Reader in the USSR is
an example. Although considered by us to be a technical success, it
nevertheless did not succeed in achieving the full benefits that were
expected because of failure on the Soviet side to provide already agreed-
upon arrangements and laboratory visits. NBS has sent a message of
protest to the Soviets in which we request an explanation of this case
before we proceed with processing of the applications of three Soviet
scientists who have applied to visit NBS under the MoC.
At present, five applications for exchange visits are pending under the
MoC--three from the Soviet side (involving three scientists), and two
from the NBS side (involving six scientists). The Soviet proposals are
in the fields of atomic and molecular spectroscopy, and the NBS proposals
are in the fields of chemical thermodynamics and measurement methodology
for non-ionizing electromagnetic radiation. We anticipate significant
scientific benefit from both of the U.S. proposals, but we are particularly
interested in the last-mentioned because of the wide difference between
current U.S. and USSR exposure standards in this area.
Assessment of Scientific and Technical Benefits and Their Balance: All
NBS participants say that the scientific benefit to their own programs
has been significant. One NBS scientist has said that only by visiting
and asking questions could he have learned all the details of the experi-
mental techniques used by Soviet scientists in his field. Such details
are ordinarily not published, or if they are published, they appear in
USSR journals or reports that are difficult to obtain and difficult to
read because of the language barrier. The NBS program of collaboration
with the USSR in the compilation and evaluation of quantitative data on
the physical and chemical properties of matter, which started several
years before the establishment of the umbrella agreement for cooperation,
has given NBS the benefit of several dozen man-years of high-quality
scientific output. Similar benefits are characteristic of all of the
cooperative interactions between NBS and USSR laboratories.
As a tangible product of the cooperation, joint publications in the
archival technical literature have appeared or are in preparation in the
fields of thermodynamic data analysis, crystal structure, molecular spec-
troscopy, and atomic spectroscopy. Several reprints of joint publications
in the latter area are attached as Attachment B. These illustrate the
contributions that joint research can make to NBS priority programs, in
this case, the provision of data useful for diagnostic work in the DOE
fusion energy efforts.
13
Page 4
In some cases, the scale of benefits is decidedly tipped in favor of NBS.
For example, NBS scientist Dr. K. Evenson reported that the Soviet effort
he observed in Novosibirsk in the field of stabilized lasers, laser
frequency measurements, and the scientific application of both of these
is about seven times greater than that currently in progress at NBS and
that their accomplishments probably surpass ours in several areas. NBS is
currently employing some techniques that were originally suggested by the
Novosibirsk group.
Dr. Kharlamov of the Soviet Academy spent most of his three-months' visit
at NBS developing computer algorithms and programs for NBS data logging
systems. He wrote and left with NBS a set of four useful computer
programs that we now use in connection with data acquisition and processing
in certain experimental areas connected with our diode laser spectrometer.
As a result of Dr. Givargizov's visit to NBS, we gained possession of a
worthwhile collection of whisker crystal specimens that he brought with
him from the USSR and that will benefit our future work.
Of course, NBS feels that it has not always received the full scope of
technical benefit that it expected. However, these cases relate to only
portions of the originally proposed programs, the remaining portions of
which were achieved to our satisfaction.
Potential for Technology Loss to the United States: At the very beginning
of implementation of the MoC, the Director of NBS established an internal
NBS Coordinating Council to approve and monitor joint activities under the
MoC to ensure that these activities provided technical benefits to NBS
and the United States. The Director serves as the Chairman of this Council.
In its appraisal of applications under the MoC, the Council pays particular
attention to the questions of reciprocity, mutual benefit, scientific
soundness, and any potential for significant technological loss to the
United States. Subject areas are limited to those considered to be basic
rather than applied research. In addition, before responding to the
Soviet Academy, NBS routinely transmits Soviet applications to the State
Department and to the Committee on Exchanges (COMEX) to obtain a thorough
inter-agency appraisal of any potential technological loss. As a result
of these evaluations and other internal considerations (such as whether
the proposed program coincides with areas of current NBS interests), NBS
has either rejected or modified several proposed Soviet visits. (No
proposed visit by NBS scientists to the USSR has been rejected by the
Soviet side.) While the Soviet visitors are in residence at NBS, care is
taken to limit their access to the agreed areas only.
14
Page 5
Cost Savings Achieved through Implemenation of the MoC: As noted above,
the budgetary outlay in the implementation of the MoC is quite modest in
comparison with the technical benefits achieved. Technical benefits
translate directly into cost savings through contributions to our own
domestic objectives. One example of cost savings and avoidance of
duplication of effort has already been mentioned--the joint production of
a compilation of critically evaluated thermophysical data that will be a
major publication of the U.S. National Standard Reference Data System
that is overseen by NBS. This effort also includes exchanges of
bibliographic references, which serves to strengthen the NBS knowledge of
the availability of Soviet data in this field--data that might otherwise
have been overlooked. During the past 2 years, the Soviet side has
provided NBS with about 60,000 microfiche images containing such information,
and NBS has provided the Soviet side with an equivalent number of
references to U.S. literature.
NBS Recommendation: In recent months, NBS has received several inquiries
from Soviet visitors and from officials in Moscow regarding NBS wishes to
renew the agreement. At a reception in early 1983 at the Soviet Embassy
in Washington, Academy Vice President Velikhov suggested that the Academy
would be interested in an extension if NBS were.
In the judgment of NBS participants, the NBS/ASUSSR program of collaboration
(1) has been of significant benefit to the technical objectives of NBS
and (2) has provided a means of acquiring information on scientific
programs within USSR laboratories that is not available from any other
source. We recommend, therefore, that if there are no overriding
objections on foreign policy grounds, authorization be given to NBS to
propose to the USSR Academy of Sciences that the existing Memorandum on
Cooperation be renewed for another five-year period.
Attachments
cc:
L. Starbird
15
ATTACHMENT B
J. Reader and A. Ryabtsev
Vol. 71, No. 3/March 1981/J. Opt. Soc. Am.
231
3p⁶ 3d8-3p5 3d⁹ transitions in Sr XIII, Y XIV, Zr XV, Nb XVI,
and Mo XVII
Joseph Reader and Aleksandr Ryabtsev*
National Bureau of Standards, Washington, D.C. 20234
Received September 29. 1980
The 3p⁶ 3d8-3p5 3d° transitions in Sr XIII, Y XIV, Zr XV, Nb XVI, and Mo XVII have been newly measured by means
of a low-inductance vacuum spark and a 10.7-m grazing-incidence spectrograph. The measurements have led to
an improved analysis of this complex transition group in these ions. All levels of the combining configurations have
been established. The energy parameters determined from least-squares fits to the observed levels are compared
with Hartree-Fock calculations. The effective interaction aL(L + 1) for the 3p⁶ 3d⁸ configuration decreases
markedly with increasing ionization. The effective electrostatic interactions D¹(3p3d) and X²(3p3d) for the
3p⁵ 3d9 configuration are practically constant through the sequence.
Ions of the isoelectronic sequence Sr XIII-Mo XVII have the
corded was about 70 A. As several important transitions for
ground configuration 3p⁶ 3d⁸. The lowest excited configu-
the present ions were expected to lie below 70 A, new expo-
ration is 3p5 3d9. In each ion the 3p⁶ 3d8-3p5 3d9 transitions
sures were taken on the 10.7-m spectrograph at an angle of
form a complex group of lines that span a region of only about
incidence of 85°. At this angle, spectra could be observed to
18 A. This region also contains complex spectra that are due
about 33 A. Wavelength-calibration procedures and further
to 3p⁶ 3dⁿ-3p⁵ 3dⁿ⁺¹ transitions of higher stages of ioniza-
experimental details are given in Refs. 4-8.
tion. The investigation of these transition groups thus re-
The wavelengths, intensities, and classifications of the
quires selective excitation and high resolution. A photograph
3p⁶ 3d8-3p5 3d9 transitions of Sr XIII-Mo XVII obtained in
of this complex spectral region for Mo, as observed in spectra
the present work are given in Table 1. The uncertainty of the
of the DITE Tokamak and a laser-produced plasma, has been
wavelengths is ±0.005 A. For perturbed lines the uncertainty
given by Mansfield et al.¹
is ±0.010 A. The intensities are visual estimates of photo-
The 3p⁶ 3d8-3p5 3d9 transitions in Y XIV, Zr XV, Nb-XV1,
graphic blackening. As noted in the table, many of the values
and Mo XVII were investigated recently by Bogdanovichene
represent new measurements for lines given originally in Refs.
et al.2 They used a low-inductance vacuum spark together
2 and 3.
with 2- and 3-m grazing-incidence spectrographs to identify
about 25 lines in each spectrum. From these identifications
ANALYSIS OF THE SPECTRA
most of the energy levels of the two configurations were es-
tablished. In a parallel investigation, Burkhalter et al.³ used
To extend the analyses we first made least-squares fits for the
a low-inductance vacuum spark and a 2.2-m grazing-incidence
most-reliably determined 3p⁶ 3d⁸ and 3p5 3d⁹ levels.² The
spectrograph to identify 14 prominent 3p⁶ 3d8-3p5 3d9
3p⁶ 3d⁸ levels included 3F2,3,4, 3P1.2, and 1D2. The 3p5 3d9
transitions in Mo XVII.
levels included 3F2,3,4, 3P1.2, ³D₁,2₃, and 1D2. These levels
In the present work we observed spectra of strontium, yt-
were confirmed by additional combinations found in the
trium, zirconium, niobium, and molybdenum with a low-
present observations. The levels 3p⁶ 3d⁸ 3P0, 1G4, 1S₀, and
inductance vacuum spark and the 10.7-m grazing incidence
3p5 3d9 3P0, 1F3, and 1P₁, which previously2 were either
spectrograph at the National Bureau of Standards (NBS).
doubtful or missing altogether in some ions, were thus ex-
With these observations we were able to extend and partially
cluded. Initial values for the parameters were taken from
revise the analyses of the ions Y XIV-Mo XVII as well as to
Hartree-Fock (HF) calculations made with the computer
provide the first spectral data for Sr XIII. About 40 lines have
program of Froese-Fischer.9 No effective interactions were
been identified in each spectrum. All levels of the 3p6 3d⁸ and
included. These calculations proved to be satisfactory from
3p5 3d9 configurations have now been established for these
the standpoint of regularity of parameter values and mean
ions.
errors. The predicted level values were thus adopted as a
basis for further analysis of the spectra.
EXPERIMENT
3p" 3d°
The measurements were taken largely from spectrograms
This level had been established by a single transition in each
made in connection with recent investigations of several highly
ion, 1D₂-¹P₁. Our new low-wavelength data provided the
charged copperlike and zinclike ions.48 These observations
3P₂-¹P₁ combinations, confirming the previous identifications
were made with the NBS 10.7-m spectrograph at an angle of
in Y, Zr, and Mo. For Nb XVI the previous 1D2-1P₁ identi-
incidence of 80°. The grating had 1200 lines/mm. At this
fication (70.474 Å) was replaced by a line at 70.718 A, resulting
angle of incidence the lowest wavelength that could be re-
in a revised value for 3p⁵ 3dº 1P₁.
232
J. Opt. Soc. Am./Vol. 71, No. 3/March 1981
J. Reader and A. Ryabtsev
3ps 3d° 1Sg
3p" 3d° 1G, and 3ps 3d° 1F₃
The 1G4-¹F₃ transition is easily identified as an intense line
This level was based on the single transition 1S₀⁻¹P₁. The
on the low-wavelength side of the transition group.²,³ It has
identification was listed² as doubtful in Y and Zr and was
the highest predicted line strength within the present array.
absent in Nb and Mo. We have now replaced these identifi-
In Ref. 2 these levels were connected to the main body of levels
cations with those given in Table 1, which includes values for
through the single transition 1G4-3D3. We have now replaced
Nb and Mo as well. These lines were the most prominent
the 1G4-3D3 identifications with those given in Table 1. This
unidentified lines in the expected region and, although there
in turn revises the 1Gs and 1F₃ level values. The new values
are no confirming transitions, there is little doubt that the
are confirmed by the four additional combinations, 3F₃¹F₃,
identifications are correct. They are strongly supported by
3FT¹F₃, 1D₂¹F₃, and 1G4-3F3. The line identified as
the least-squares calculations.
1G4-3D₃ in Y XIV was previously identified as 3P₁-³P₀
Table 1. Observed 3p' 3d8-3p5 3d' Transitions in Sr XIII, Y XIV, Zr XV, Nb XVI, and Mo XVII
Sr XIII
Y XIV
Zr XV
Nb XVI
Mo XVII
Transition
X(A)
Int.
X(A)
Int.
X(A)
Int.
X(A)
Int.
A(A)
Int.
3pe 3d8 3Fs-3p5 3d° 1F3
76.229
10
72.455
10
68.989
10
65.770
4
3F2-3p5 3d° 1F₃
76.506
1h
72.692
1h
69.174
2
65.891
1h
3P2-3p5 3d9 ip₁
77.268
25
73.239
15
69.540
15
66.100
3
1D2-3p5 3d° 1P₁
82.758
75
78.395ᵇ
50p
74.395
40
70.718
40
67.302ᶜ
15
1D2-3p5 3d° 1F₃
78.813
10
74.966
3
71.448
5
68.188
3h
1G4-3p5 3d° 1F3
83.656
2000
79.338b
3000
75.385ᵇ
2000
71.759
1200
68.390
800
3F3-3p5 3d° 3P2
85.311
120
80.714b
150
76.509b
70
72.656
100
69.088
30
3F2-3ps 3d° 3P2
81.030ᵇ
20
76.777
10
72.870
5
3P2-3p5 3d° 3P2
82.334
50
78.006ᵇ
20
74.049
20
70.386
15
3F3-3p5 3d° 3F2
82.628
5
74.132
2
70.367
3
3F2-3p5 3d° 3F2
87.831
100
82.963ᵇ
120
78.483b
30
74.352
20
70.494
5
3P1-3p5 3d° 3P2
88.151
200
83.397ᵇ
140
79.046ᵇ
70
75.060
70
71.359°
30
1D2-3ps 3d° 3P2
83.614
70
79.318
15
71.750
5
1So-3p5 3d° 1P1
88.631
70
83.970
50
79.689
30
75.754
20
72.092
20
3F2-3p5 3d° 3D₁
88.568
500
84.211b
200
80.247ᵇ
250
76.631ᵇ
120
73.289ᶜ
200
3F4-3p5 3d° 3D₃
88.754
800
84.266ᵇ
400
80.176b
400
746.442b
300
72.990
300
3P2-3p3 3d° 3F2
84.326
25
79.766
2h
75.590
20p
71.705
7
3F3-3p5 3d⁹ 3D₃
89.797
200
85.372ᵇ
160
81.350b
250
77.685ᵇ
120
74.306ᶜ
200
3P2-3ps 3d° ³D₁
85.618ᵇ
25
77.9496
30
74.600
5
1D2-3p5 3d° 3F2
90.618
150
85.673b
150
81.140ᵇ
200
76.980ᵇ
120
73.122c
150
3Po-3p5 3d° 3D₁
91.253
60
86.767ᵇ
70
82.696ᵇ
25
78.986ᵇ
40
75.580
15
3F3-3p5 3d° 3D2
91.481
500
87.009ᵇ
400
82.948
300
79.241
500
75.840ᵇ
150
3P2-3p⁵ 3d° 3D3
91.757
100
87.184b
100
83.048ᵇ
100
79.284b
50p
75.816
15
3Fs-3p5 3d° 3F₃
92.664
600
87.984ᵇ
600
83.727b
700
79.839b
500
76.269ᶜ
600
3P2-3p5 3d° 3P₁
92.734
150
88.186ᵇ
140
84.061ᵇ
100
80.298ᵇ
150
76.863ᵇ
200h
1D2-3p5 3d° 3D3
88.623
5
84.534
2
77.396
5p
3P₂-3p⁵ 3d° 3D2
93.517
150
88.893ᵇ
150
84.708b
100
80.890ᵇ
80
77.4106
20
3P1-3p5 3d° 3Po
93.772
80
89.190d.e
600
85.031ᵇ
200
81.213°
80
77.727
30
3F3-3ps 3d° 3F3
93.800
100
89.190d,e
600
85.011
70
81.202
100
77.706
20
1G4-3p5 3d⁹ 3D3
93.967
50
89.287ᵈ
75
85.064
30
81.213
80
77.666ᵇ
30
3Po-3ps 3d° 3P₁
89.408d.e
150
85.236
20
81.412₫
20
77.898
15
3P1-3p5 3d° 3P₁
89.408b,e
150
85.269ᵇ
40
81.489
80
78.019ᵇ
40
1D23p5 3d° 3D2
94.955
50
90.389ᵇ
120
86.256ᵇ
70
82.495'
50
79.062b
100
3F4-3p5 3dº 3F4
95.528
1500
90.871ᵇ
1500
86.630ᵇ
1500
82.749b
1500
79.186
1500
3Fs-3ps 3d° 1D2
90.967
5
82.993
50bl
79.532
5
3P2-3p5 3d° 3F3
91.177
5h
82.945
2
79.359
5
3Fz3p8 3d° 1D2
95.998
400
91.371ᵇ
600
87.147b.s
600
83.275b
600
79.711ᶜ
700
3Fs-3p5 3d° 3Fs
96.739
200/
92.160
40
88.006ᵇ
20h
84.211b
100
80.734
30
1D23p5 3d° 3F3
97.450
100
92.749
25
88.486
20
84.619
40
81.080
20p
3P2-3ps 3d° 1D2
97.766
400
93.031b
400
88.732b
300
84.823b
150
81.261ᵇ
100
1G4-3p5 3d° 3F₃
93.478
15
89.069
20
85.058
10
81.382
20
³P₁-3p⁵ 3d° 1D2
94.390
10
90.080
10
86.154
30
82.556
20
1D2-3p⁵ 3d° 1D2
99.341
100
94.671b
100
90.434b
100
86.586ᵇ
30
83.079ᵇ
50
a
Symbols: bl, blend of two lines; h, hazy; P. perturbed by close line.
b
Present value for line given originally by Bogdanovichene et aL, Ref. 2.
Present value for line given originally by Bogdanovichene et al., Ref. 2, and by Burkhalter et al., Ref. 3.
d
Present value for line given originally by Bogdanovichene et al, Ref. 2, revised classification.
. Doubly classified.
/ Blended with 96.731 A of Ti. (The Sr exposures were made with an anode of Sr and a cathode of Ti.)
8 Blended with a line of Zz XII; see Ref. 7.
17
J. Reader and A. Ryabtsev
Vol. 71, No. 3/March 1981/J. Opt. Soc. Am.
233
Table 2. Energy Levels (in cm⁻¹) of the 3p' 3dª and 3p5 3d° Configurations of Sr XIII, Y XIV, Zr XV, Nb XVI, and
Mo XVII
Configuration
Term
J
Sr XIII°
Y XIV
Zr XV
Nb XVI
Mo XVII
3p⁶ 3d⁸
3F
4
0
0
0
0
0
3
13 080
15 380
18 030
20 960
24 250
2
18 000
20 230
22 560
24 890
27 030
sp
2
36 850
39760
43 080
46 840
51 000
0
51 230
55230
59 470
63 830
68 350°
1
50840
55 240
59 940
65 020°
70 310
ID
2
53 040
58 380
64 280
70 790
77 960
1G
4
62 500
66 780°
71 660a
76 870°
82 420°
is
0
133 120
143 060°
153 590°
164 790°
176 700*
3p⁵ 3d°
3F
4
1 046 800
1 100 460
1 154 330
1 208 470
1 262 860
1D
2
1 059 690
1 114 670
1 170 060
1 225 740
1 281 600
3F
3
1 079 180
1 136 550
1 194 370
1 252 520
1 311 160
³D
2
1 106 180
1 164 700
1 223 610
1282970
1 342 800
3P
1
1 115 200
1 173 720
1 232 700
1 292 180
1 352 050
3P
0
1 117 250
1 176 440a
1 235 980°
1 296 360°
1 356 860°
3D
3
1 126 700
1 186 740
1 247 240
1 308 200
1 370 010
³D
1
1 147 080
1 207 730
1 268 720
1 329 840
1 391 470
de
2
1 156 570
1 225 610
1296720
1 369 820
1 445 570
3P
2
1 185 260
1 254 340
1 325 040
1 397 270°
1 471 690
1F
3
1 257 880
1 327 220°
1 398 200°
1 470 450°
1 544 660°
1P
1
1 261 390
1 333 960
1 408 460
1 484 850°
1 563 830
New level; all levels for Sr XIII are new.
3p⁵ 3d° 3Po
electronic regularities. The evidence for a blend in Y is par-
This level makes only one combination within the present
ticularly strong because there is no other possible choice
array, 3P₁-³P₀. Although this transition is expected to be
within a reasonable distance of the predicted position and,
fairly strong, its identification is made difficult by the com-
furthermore, the other member of the blend, 3F₃-³F₃, appears
plexity of the spectrum in the expected region. Based on the
to be anomalously strong compared with its appearance
present observations and calculations, we propose the new
elsewhere in the sequence.
identifications for this transition given in Table 1. In Zr and
Mo there is not much doubt about the assignments, because
3p5 3d° 3P,
there is only one clear choice. In Y and Nb the proposed lines
This level can make three transitions, of which two, 3P₀-³P₁
represent blends with other transitions of the same array.
and 3P₀-³D₁, are expected to be reasonably strong and one,
However, these identifications are well supported by iso-
³P₀-¹P₁, is expected to be weak. In Ref. 2, values for 3Po were
's
10
1F
160
Mo XVN
2p⁶³d⁸
1500
Mo XVS
120
3p53d9
i Energy GOBL)
1a
B
'D
Iffent case)
1490
2p
30
3p
40
.
1329
10
0
2F
0
1
2
3
4
0
1
2
3
4
J Value
J Value
Fig. 2. Structure of the 3p5 3d° configuration of Mo XVII. Levels
Fig. 1. Structure of the 3pᵉ 3d⁸ configuration of Mo XVII.
are grouped into LS terms.
234
J. Opt. Soc. Am./Vol. 71, No. 3/March 1981
J. Reader and A. Ryabtsev
(1/2, 3/2)
given for Y, Zr, and Nb based on the single transition 3Pσ³D₁.
No value was given for Mo. We have now observed the
(1/2, 5/2)
3Po-3D₁ as well as the 3Po-3P1 transition for the present ions,
confirming the previous identifications and providing values
1500
for Mo. In Y the 3p⁶ 3d⁸ 3P₀ and 3P₁ levels are nearly coin-
cident and the 3Po-3P1 and 3P₁-³P₁ transitions thus cannot
Mo XVS
be resolved. Our value for ³Pσ-³D₁ in Mo replaces the iden-
3p53d9
tification for this transition given in Ref. 3.
i Enery
Sr XIII
1480
The spectra for this ion were relatively weak, but with the help
of isoelectronic regularities the principal lines of the array and
(3/2, 3/2)
all of the levels could in fact be located. The presence of
3P1-³P₀ as a fairly strong line in Sr further supports the pro-
posed blend of 3P₁-³P₀ and 3F3-3F3 in Y.
Finally, we confirm the value for 3F₃-³D₂ of Mo XVII given
1300
in Ref. 2 (75.843 A), compared with the value given in Ref. 3
(3/2. 5/2)
(75.624 A). The resulting levels are supported by several
other combinations.
0
1
2
3
4
The values of the energy levels are given in Table 2. These
J Value
values were determined by an optimization procedure¹⁰ that
minimizes the differences between the observed and calcu-
Fig. 3. Structure of the 3p⁵ 3d° configuration of Mo XVII. Levels
lated wave numbers. The uncertainty of the level values is
are grouped into jj terms.
about ±50 cm⁻¹.
Table 3. Energy Parameters (in cm⁻¹) and Mean Errors A of Least-Squares Fits for the 3p⁶ 3d⁸ Configurations
of Sr XIII, Y XIV, Zr XV, Nb XVI, and Mo XVII."
Ion
Parameter
HF
Fitted
Fitted-HF
Sr XIII
Eav
36440
34 031 ± 63
F²(3d3d)
214 978
194 218 ± 513
0.903 ± 0.002
F4(3d3d)
136 981
115 570 ± 468
0.844 ± 0.003
α(3d3d)
203 ± 12
Isd
6133
207 ± 74
1.012 ± 0.012
A
167
Y XIV
Eav
39578
37 009 ± 61
F²(3d3d)
225 641
204 477 ± 496
0.906 ± 0.002
F4(3d3d)
143 929
123 560 ± 456
0.858 ± 0.003
α(3d3d)
171 ± 11
Sad
7 196
7 226 ± 70
1.004 ± 0.010
A
161
Zr XV
Eav
42883
40 323 ± 82
F²(3d3d)
236 241
215 429 ± 678
0.912 ± 0.003
F4(3d3d)
150 838
131 717 ± 627
0.873 ± 0.004
a(3d3d)
156 ± 15
S3d
8 388
8 365 ± 92
0.997 ± 0.011
A
218
Nb XVI
Eav
46430
43 903 ± 103
F²(3d3d)
246787
226 602 ± 847
0.918 ± 0.003
F*(3d3d)
157 711
140 221 ± 789
0.889 ± 0.005
α(3d3d)
138 ± 19
3d
9717
9 641 ± 108
0.992 ± 0.011
A
272
Mo XVII
Eav
50 238
47 735 ± 118
F2(3d3d)
257 286
238 019 ± 975
0.925 ± 0.004
F*(3d3d)
164 554
149 180 ± 918
0.907 ± 0.006
a(3d3d)
123 ± 22
S3d
11 195
11 080 ± 117
0.990 ± 0.010
A
312
. The value of Egv listed in the HF column is that obtained by diagonalizing the energy matrix with the HF parameters, 3Fa level set at zero.
19
J. Reader and A. Ryabtsev
Vol. 71, No. 3/March 1981/J. Opt. Soc. Am.
235
Table 4. Percentage Compositions for the 3ps 3d⁸
The levels of the 3p⁶ 3d⁸ configuration of Mo XVII are
Levels of Sr XIII, Zr XV, and Mo XVII
plotted in Fig. 1. Although a few distortions are evident, the
J Term
Percentage Composition (LS)
levels can be designated fairly well in the LS scheme. The
3p⁵ 3d° levels of Mo XVII are plotted with LS designations in
0 sp 96, 95, 93% 3P + 4, 5, 7% is
Fig. 2 and with jj designations in Fig. 3. Clearly, neither
IS 96, 95, 93% is + 4, 5, 7% 3P
scheme is satisfactory. Although, as discussed below, the
1
3P 100, 100, 100% 3P
coupling is a little closer to jj than to LS, we have retained LS
2
3F 79, 69, 57% 3F + 19, 27, 34% 'D + 2. 4, 9% 3P
designations for the levels in order to facilitate comparison
sp 47, 52, 55% 3P + 37, 24. 12% ID + 16, 24, 33% 3F
with Ref. 2, in which LS designations are used throughout.
ID 45, 50, 52% 1D + 51, 43, 37% 3P + 4, 7, 11% 3F
3
3F 100, 100, 100% 3F
THEORETICAL INTERPRETATION
4 3F 99, 99, 98% 3F + 1, 1, 2% 1G
1G 99, 99, 98% G + 1, 1, 2% 3F
The results of fitting the theoretical energy parameters to the
observed 3p⁶ 3d⁸ level values by least-squares calculations are
Table 5. Energy Parameters (in cm⁻¹) and Mean Errors A of Least-Squares Fits for the 3p5 3d° Configurations
of Sr XIII, Y XIV, Zr XV, Nb XVI, and Mo XVII
Ion
Parameter
HF
Fitted
Fitted-HF
Sr XIII
Eav
1 112 692
1 131 577 ± 46
F²(3p3d)
202 415
193 004 ± 546
0.954 ± 0.003
G¹(3p3d)
235 516
199 797 ± 237
0.848 ± 0.001
G³(3p3d)
150 323
141 352 ± 456
0.940 ± 0.003
D¹(3p3d)
-13 736 ± 412
X²(3p3d)
-6 063 ± 569
53p
55 838
58 728 ± 87
1.052 ± 0.002
53d
6096
5 984 ± 60
0.982 ± 0.010
A
148
Y XIV
Esv
1 166 512
1 192 951 ± 60
F²(3p3d)
210 891
201 963 ± 736
0.958 ± 0.003
G¹(3p3d)
244 026
208 819 ± 312
0.856 ± 0.001
G³(3p3d)
156 264
147 262 ±617
0.942 ± 0.004
D¹(3p3d)
-13 522 ± 544
X²(3p3d)
-5 883 ± 743
53p
63880
67 429 ± 110
1.056 ± 0.002
53d
7152
7 004 ± 78
0.979 ± 0.011
A
193
Zr XV
Esv
1 220 111
1 255 174 ± 83
F²(3p3d)
219 314
210 733 ± 1056
0.961 ± 0.005
G¹(3p3d)
252 433
218 008 ± 438
0.864 ± 0.002
G³(3p3d)
162 142
153 534 ± 889
0.947 ± 0.005
D¹(3p3d)
-13 722 ± 764
X²(3p3d)
-6 304 ± 1038
Sp
72760
77 094 ± 148
1.060 ± 0.002
53d
8 335
8 162 ± 107
0.979 ± 0.013
s
267
Nb XVI
Eav
1 274 595
1 318 169 ± 117
F²(3p3d)
227 690
219 792 ± 1527
0.965 ± 0.007
G¹(3p3d)
260 752
226 922 ± 622
0.870 ± 0.002
G³(3p3d)
167 965
159 526 = 1295
0.950 ± 0.008
D¹(3p3d)
-13 771 ± 1085
X²(3p3d)
-7 039 ± 1469
53p
82 533
87 640 # 204
1.062 ± 0.002
53d
9657
9 475 ± 148
0.981 ± 0.015
A
374
Mo XVII
Eav
1 328 831
1 382 222 ± 132
F²(3p3d)
236 026
228 252 ± 1772
0.967 ± 0.008
G¹(3p3d)
268 994
235 911 ± 713
0.877 ± 0.003
G³(3p3d)
173740
165 595 ± 1518
0.953 ± 0.009
D¹(3p3d)
-14 052 ± 1242
X²(3p3d)
-6 745 ± 1679
53p
93255
99 559 ± 226
1.068 ± 0.002
53d
11 125
10 918 ± 166
0.981 ± 0.015
0
422
20
236
J. Opt. Soc. Am./Vol. 71, No. 3/March 1981
J. Reader and A. Ryabtsev
Table 6. Percentage Compositions for the 3p⁵ 3d° Levels of Sr XIII, Zr XV, and Mo XVII
J
Term
Percentage jj
Percentage Composition (LS)
0
3P
100, 100, 100% (3/2,3/2)
100, 100, 100% 3P
1
sp
81, 78, 75% (3/2,3/2)
84, 85, 86% 3P + 16, 14, 12% 3D + 0, 1, 2% 1P
³D
63, 66, 66% (3/2,5/2)
68, 65, 63% 3D + 22, 27, 32% 1P + 10, 8, 5% 3P
1P
80, 85, 89% (1/2,3/2)
78, 72, 66% 1P + 16, 20, 25% 3D + 6, 8, 9% 3P
2
1D
70, 73, 77% (3/2,5/2)
75, 74, 73% 1D + 17, 15, 14% 3F + 8, 10, 12% 3P
3D
67, 72, 76% (3/2,3/2)
45, 49, 51% 3D + 31, 31, 31% 3P + 23, 20, 18% 3F
3F
93, 96, 98% (1/2,3/2)
59, 63, 66% 3F + 19, 20, 20% ID + 12, 9, 7% 3D
3P
97, 98, 98% (1/2,5/2)
51, 51, 51% 3P + 43, 42, 41% 3D + 5, 6, 6% 1D
3
3F
66, 63, 60% (3/2,3/2)
79, 72, 65% 3F + 21, 27, 34% 3D
3D
66, 62, 58% (3/2,5/2)
75, 66, 57% ³D + 17, 22, 28% 3F + 8, 12, 15% 1F
1F
62, 67, 71% (1/2,5/2)
91, 88, 84% 1F + 5, 7, 9% 3D + 4, 5, 7% 3F
4
3F
100, 100, 100% (3/2,5/2)
100, 100, 100% 3F
given in Table 3. The HF values of the parameters are also
values shown in Table 3 are generally close to unity. This is
given here. The parameter a for the effective electrostatic
surprising because the HF calculation⁹ does not include the
interaction aL(L + 1) is small but well defined. Its intro-
effects of relativity. The ratios vary smoothly through the
duction into the calculation reduced the mean error of the fit
sequence.
considerably; for Y XIV, for example, the mean error decreased
The percentage compositions for the 3p⁶ 3d⁸ configurations
from 1300 to 161 cm⁻¹. The present values of a are consistent
of Sr XIII, Zr XV, and Mo XIII are given in Table 4. As already
with the value of 108 cm⁻¹ obtained by Podobedova et al. 11
noted, the coupling is close to LS, although the 3P2 and 1D2
for the isoelectronic ion Ge VII. A value for a of 48 cm⁻¹ was
states are strongly admixed.
obtained by Meinders¹² for Cu IV, but this fit included two
The parameters for the 3p⁵ 3d⁹ configurations are given in
additional effective interactions, so a direct comparison may
Table 5. The fitted-HF ratios are again close to unity and
not be valid. Interestingly, for the present series of atoms,
vary smoothly through the sequence. The parameters
a decreases significantly with increasing ionization.
D¹(3p3d) and X²(3p3d) for the direct and exchange effective
The ratios of the fitted values of the parameters to the HF
electrostatic interactions¹³ are well defined. Of the two, the
direct interaction D¹(3p3d) is the more important. Its in-
Table 7. Differences between Observed Level Values
troduction into the calculation reduced the mean error for Y
and Those Calculated with the Fitted Values of the
Parameters for the 3p' 3d⁸ and 3p5 3d° Configurations
XIV from 2300 to 700 cm⁻¹. Addition of X²(3p3d) further
of Sr XIII, Y XIV, Zr XV, Nb XVI, and Mo XVII (in cm⁻¹)
reduced the mean error to 193 cm⁻¹. [When X²(3p3d) is
added alone, the mean error is reduced only to 2200 cm⁻¹.]
Configuration J Term Sr XIII Y XIV Zr XV Nb XVI Mo XVII
These parameters are thus significant. Their values are
nearly constant through the sequence.
3p6 3d⁸
0
3P
110
100
110
30
10
is
-20
10
30
40
70
The percentage compositions for the 3p⁵ 3d9 configurations
1
3P
-110
10
70
190
220
of Sr XIII, Zr XV, and Mo XVII are given in Table 6. As already
2
3F
220
220
210
180
-10
mentioned, the major components in the jj scheme are gen-
3P
80
-110
-220
-250
-230
erally higher than in the LS scheme. In the jl scheme the
ID
-80
-130
-180
-240
-290
major component percentages were found to be a little lower
3
3F
-90
30
150
270
420
on the average than in the jj scheme.
4
3F
-130
-110
-160
-180
-150
The differences between the observed level values and those
1G
0
-10
-20
-20
-40
calculated with the fitted values of the parameters are given
3p5 3d°
0
3P
10
100
90
160
120
in Table 7. The differences generally vary smoothly, although
1
sp
-110
-240
-280
-410
-370
there are a few irregularities, such as for 3p⁶ 3d⁸ 3F2 and 3P2.
3D
100
-10
-60
-150
-220
In view of the uncertainties of the level values, we do not
1P
-30
0
30
70
120
consider these irregularities to be significant.
2
ID
10
20
30
50
60
3D
80
150
230
310
340
A. Ryabtsev would like to thank W. C. Martin for generous
3F
-70
-110
-170
-240
-290
hospitality in making possible his stay as a guest worker at
sp
90
110
160
200
220
NBS. This work was supported in part by the Office of
3
3F
100
120
200
250
330
Magnetic Fusion Energy of the U.S. Department of En-
$D
-190
-140
-220
-270
-360
ergy.
1F
20
10
30
40
70
Permanent address, USSR Academy of Sciences, Institute
4
3F
-30
-40
--40
-20
0
for Spectroscopy, Troitsk, Moscow Region 142092, USSR.
J. Reader and A. Ryabtsev
Vol. 71, No. 3/March 1981/J. Opt. Soc. Am.
237
REFERENCES
8. J. Reader and N. Acquista, "Spectrum and energy levels of
twelve-times ionized niobium (Nb XIII)," J. Opt. Soc. Am. 70,
1. M. W.D. Mansfield et al., "The XUV spectra of highly ionized
317-321 (1980).
molybdenum," J. Phys. B 11, 1521-1544 (1978).
9. C. Froese, "Numerical solution of the Hartree-Fock equations,"
2. M. I. Bogdanovichene et al., "3d8-3p5 3d° transitions in spectra
Can. J. Phys. 41, 1895-1910 (1963); C. Froese-Fischer and M.
of Y XIV-Mo XVII," Opt. Spektrosk. 49, 447-452 (1980).
Wilson, "Programs for atomic structure calculations," Argonne
3. P. G. Burkhalter, J. Reader, and R. D. Cowan, "Spectra of Mo
National Laboratory Report No. 7404 (National Technical In-
XIII-XVIII from a laser-produced plasma and a low-inductance
formation Service, Springfield, Va., 1968).
vacuum spark," J. Opt. Soc. Am. 70, 912-919 (1980).
10. Optimization of the level values was done with the computer
4. J. Reader and N. Acquista, "48-4p resonance transitions in highly
program ELCALC programmed by L. J. Radziemski, Jr.
charged Cu- and Zn-like ions," Phys. Rev. Lett. 39, 184-187
11. L. I. Podobedova, A. A. Ramonas, and A. N. Ryabtaev, "Analysis
(1977).
of the spectrum of Ge VII," Opt. Spektrosk. 49, 453-459 (1980).
5. J. Reader, G. Luther, and N. Acquista, "Spectrum and energy
12. E. Meinders, "Revised analysis of the Cu IV spectrum," Physica
levels of thirteen-times ionized molybdenum (Mo XIV)," J. Opt.
(Utrecht) 84C, 117-132 (1976).
Soc. Am. 69, 144-149 (1979).
13. This notation for the effective electrostatic interactions is that
6. J. Reader and N. Acquista, "Spectrum and energy levels of ten-
given by J. Sugar and V. Kaufman, "Fourth spectrum of lute-
times ionized yttrium (Y XI)," J. Opt. Soc. Am. 69, 1285-1288
tium," J. Opt. Soc. Am. 62, 562-570 (1972). In our energy matrix
(1979).
the coefficients of D¹(3p3d) are [5]1/2/10 for 1,3P, [5]1/2/30 for 12D,
7. J. Reader and N. Acquista, "Spectrum and energy levels of
and -[5]1/2/15 for 1,3F; the coefficients of X²(3p3d) are 1/10 for
eleven-times ionized zirconium (Zr XII)," J. Opt. Soc. Am. 69,
1P, - 1/10 for 3P, -1/6 for 'D, 1/6 for 3D, -1/15 for 1F; and 1/15
1659-1662 (1979).
for 3F.
22
692
J. Opt. Soc. Am./Vol. 71, No. 6/June 1981
Wyart et al.
3d-4p Transitions in the zinclike and copperlike ions Y X, XI;
Zr XI, XII; Nb XII, XIII; and Mo XIII, XIV
Jean-François Wyart,* Joseph Reader, and Aleksandr Ryabtsev+
National Bureau of Standards, Washington, D.C. 20234
Received December 16, 1980
Lines occurring as satellites on the long-wavelength side of the 3d¹⁰-3d⁹₄p resonance lines of Ni-like ions have been
investigated with a low-inductance vacuum spark and a 10.7-m spectrograph for the elements Y, Zr, Nb, and Mo.
The lines are interpreted as 3d¹⁰4s-3d³4s4p and 3d¹⁰⁴p-3d⁹⁴p² transitions in the Cu-like ions Y XI, Zr XII,
Nb XIII, and Mo XIV and 3d104s2-3d94s24p transitions in the Zn-like ions Y X, Zr XI, Nb XII, and Mo XIII. The
spectra of the Cu-like ions were interpreted by generalized least-squares fits for the energy levels of the sequence
of four ions. Thirty-nine levels of 3d°4s4p were interpreted simultaneously with a root-mean-square deviation
of 122 cm⁻¹; forty-four levels of 3d°4p2 were interpreted in the same way with a root-mean-square deviation of
200 cm⁻¹. Line identifications and energy levels were obtained for the 3d¹⁰⁷P configuration of the Cu-like ions
Y XI-Mo XIV.
The use of highly ionized molybdenum for plasma diagnosis
LINE IDENTIFICATIONS AND THEORETICAL
in controlled-fusion research has stimulated spectroscopic
INTERPRETATION
investigations of this element in recent years. As a member
of the Cu I isoelectronic sequence, Mo XIV has the ground
3d"4s-3d"4s4p Transitions
configuration 3d¹⁰4s. Its one-:lectron spectrum and those
As was seen in Mo XIV,5 the strongest satellite lines are due
of the neighboring members of the sequence Y XI, Zr XII, and
to 3d¹⁰4s-3d⁹4s4p transitions. We thus interpreted these
Nb XIII have already been well described.¹-⁴ In a recent de-
transitions first. The 3d94s4p configuration contains 23
scription⁵ of the spectra of Mo XIII-XVIII from laser-produced
levels, of which eleven have J = 1/2 or 3/2 and can therefore
plasmas and low-inductance vacuum sparks, satellite lines
combine with 3d¹⁰₄s 2S1/2. Our line identifications were
occurring on the high-wavelength side of the 3d¹⁰-3d⁹₄p
made with the help of theoretical calculations of the
resonance transitions of the Ni-like ion Mo XV were inter-
3d³4s4p-level structures and 3d¹⁰⁴s-3d⁹4s4p line strengths
preted as 3d¹⁰4s-3d⁹4s4p transitions of Mo XIV and
in the four ions that were investigated. Initial energy pa-
3d104s2-3d94s24p transitions of Mo XIII. Unfortunately,
rameters for the 3d94s4p configurations were obtained by
three prominent lines near the middle of the satellite group
Hartree-Fock (HF) calculations.⁷ After identifying the
remained unexplained.
strongest and most reliable transitions in each ion, we repeated
In the present work we photographed spectra of Y, Zr, Nb,
the calculations with values of the parameters determined
and Mo on the 10.7-m grazing-incidence spectrograph at the
from least-squares fits to the observed energy levels. New line
National Bureau of Standards (NBS) and theoretically in-
identifications were then carried out. In this way, 10 of the
terpreted the corresponding satellite line groups in each of
11 possible transitions in each ion could be identified. Only
these spectra. The unexplained lines in Mo were interpreted
the transition 3d¹⁰4s which is
as 3d¹⁰⁴p-3d⁸⁴p² transitions of Mo XIV.
calculated to be 400 times weaker than the strongest transition
of the array, could not be identified. The low calculated line
EXPERIMENT
strength for this transition results from the fact that the upper
level corresponds to a fairly pure 2D3/2 state. The previous⁵
The experimental material for this work was the same as used
identification of this transition in Mo XIV is probably spu-
for a recent study of 3p63d8-3p⁵3d⁹ transitions of Y XIV,
rious.
Zr XV, Nb XVI, and Mo XVII.⁶ Briefly, the 10.7-m grazing-
The wavelengths and classifications of the identified
incidence spectrograph at NBS was used at angles of incidence
3d¹⁰⁴s-3d³4s4p transitions are given in Table 1. The un-
of 80° and 85° to record spectra from a low-inductance vac-
certainty of the wavelengths is ±0.005 A. The intensities are
uum spark between metallic electrodes. The grating had 1200
visual estimates of photographic plate blackening. The line
lines/mm. The plate factor was about 0.12 A/mm at the 85°
identifications are well supported by the calculated line
angle of incidence.
strengths, which predict the observed trends well. Because
Wyart et al.
Vol. 71, No. 6/June 1981/J. Opt. Soc. Am.
693
Table 1. Lines Classified as 3d'04s-3d'4s4p and 3d¹⁰⁴p-3d⁴p² Transitions in Y XI, Zr XII, Nb XIII, and Mo XIVᵃ
Y XI
Zr XII
Nb XIII
Mo XIV
Classification
Code
1 (A)
Int.
1 (A)
Int.
1 (A)
Int.
1 (A)
Int.
4a 2S1/F-(2D, 1P)
A
73.639
15
64.466
20
57.001
15
50.788
10
4p 1S)
a
73.908
2
64.794
lw
57.393
2
51.20
1
4p ³P) 4P3/2
b
74.175?
1
57.187
1
4p 2Pi/F(2D, 3P)
c
74.391
5
65.059
2
57.468
2
51.158
1
4a 2S₁/₂-(3D, ¹P)
B
74.456
30
65.200
50
57.662
30
51.398
20
4p 2Pi/F(2D, ¹D) 2D3/2
d
74.896
8
65.466
5
57.797
3
51.434
1
4p ¹D) 2F5/2
e
74.954
2p
65.540
3
57.884
2
51.531
1
4p 3P) 4P₁/₂
f
65.609
1
4p 3P) 4Pa/2
g
75.209
10
4p 2Pi/F(2D, 3P) &F3/2
h
75.233
15
65.760
10
58.053
10
51.666
5
4p ³P) 2P3/2
i
75.307
25
65.896
10
58.241
15
51.894
8
4p 1D) 2P1/2
j
65.816?
1
4p 3P) 2P₁/2
k
75.438
10
66.029
5
58.362
5
52.00
2u
4p 2Pi/T(2D, 3P) 2D5/2
1
75.521
35
66.080
20
58.386
20
52.013
10u
4p 2Pi/π-(2D, 3P) 2D3/2
m
75.584
25
66.115
10
58.407
10
52.019
8u
4p 2Pi/F(2D, 3P) 4D1/2
n
75.945
2
66.327
2
4a 2S1/2-(2D, 3P) 4Di/2
C
76.274
25
66.597
8
58.728
10
52.225
5
4p 2Pi/F(2D, ¹D) 2P3/2
o
76.283?
2u
66.687?
3
58.888*
5
52.415*
2
4p ²Pi/₂-(²D, ³P) 4F3/2
P
58.909
3
4p 2Pi/F-(2D, 1D) 2S1/2
q
76.331
10
66.717
5p
58.888*
5
52.415*
2
4p 2Pi/2-(2D, ¹D)
r
76.434?
15l
66.792?
5
4p 3P) 4D3/2
s
76.584?
15
4a 2S1/F-(2D, 3P) 4Dip
D
76.66
1
66.928
3
59.016
5w
52.473
5
4a 2S₁/₂-(2D, 3P) 2Pin
E
76.843
40
67.121
30
59.214
20
52.687
10
4s 2S₁/₂⁻(²D, 3P)
F
76.920
50
67.201
50
59.285
40
52.750
20
4s 2S1/2-(2D, 3P) 2Di/2
G
77.340
35
67.569
30
59.612
20
53.044
10
4p ¹D)
t
59.826
2
4p 2Pi/r-(2D, ¹D) 2S₁/2
u
77.436
51
4a 251/F(2D, ³P) 4Pin
H
77.667
5.
67.768
5
59.722
5
53.095
3
4s 3P) 4F3/2
I
77.910
5w
68.022
2
59.971
5
53.335
3
4a 4Pi/2
J
78.424
25
68.476
15
60.383
10
53.725
5
Levels are designated in LS coupling: The parent terms for 3d and for the coupled external electrons 4s4p or 4p2 are given in parentheses. A code has been
attributed to the transitions to facilitate correspondence with Fig. 1. Capital letters-denote 3d¹⁰⁴s-3d*4s4p transitions; lower-case letters denote 3d¹⁰⁴p-3d⁸⁴p²
transitions. Symbols: u, unresolved; w, wide; 1, shaded to longer wavelengths; p, perturbed by close line; : doubly classified. Lines for which a question mark
is given have observed intensities much larger than expected; they may be blended with lines of other ionization stages. Not all the transitions are shown in Fig.
1.
the transitions may be written as [3d¹⁰(15)]4s-
configurations. For example, the 3d¹⁰⁷p configuration
[3d°4p(L,S)]4s, the intensities are proportional to the amount
overlaps 3d94s4p and, as the relative position of the two
of [3d°4p(¹P)]4s 2Pi/2 state in the upper level. For the line
configurations varies along the sequence, different repulsion
marked D in Fig. 1, this is calculated as 4.9% for Mo, 3.9% for
effects may be expected. As the ratio of observed levels to free
Nb, 2.5% for Zr, and 0.9% for Y. Therefore the low intensity
parameters is small, the parameter values are thus sensitive
found for this transition in Y XI is theoretically justified.
to such small perturbations.
Tracings of a portion of the satellite spectra observed in each
In order to reduce the number of free parameters and im-
element are shown in Fig. 1.
prove their reliability, we adopted a generalized least-squares
The least-squares calculation for the 3d94s4p levels involves
(GLS) procedure in which the four observed spectra were
fitting the ten observed levels with the eight Slater parameters
treated simultaneously. In this procedure the HF values of
for the 3d94s4p configuration: A, F2(3d4p), G¹(3d4p),
the integrals were entered explicitly into the energy matrices
G³(3d4p), G¹(4s4p), G²(3d4s), S3d, and S4p. As G³(3d4p)
as coefficients of the angular factors and the scaling factors
has a constant contribution to the terms having J = 1/2,
for the HF parameters considered as free parameters. The
levels (2AP, 2,4D, 4F), its value could be fixed at the HF value,
scaling factors SF(Z) were constrained to be linearly depen-
leaving seven parameters to be varied.
dent on Z: SF(Z) - SFav + (Z Zav). (For the present
By optimizing the remaining seven parameters, we could
ions, Zav = 40.5.) However, with this constraint, the coeffi-
obtain good agreement between calculated and observed
cient a of the linear term in the GLS procedure was undefined
energies. Also, the resultant scaling factors for the HF pa-
for all parameters except G¹(4s4p) and Sad- We thus set a
rameters of the four ions were found to be quite similar.
= 0 except for these two parameters, leaving 13 parameters
Nevertheless, their variation along the sequence was not
to account for the 40 observed levels. The resultant root-
completely regular. The irregularities are undoubtedly due
mean-square deviation of this fit, 122 cm⁻¹, is comparable
to small perturbations that may be expected for such high
with the uncertainty of the energy-level values, which is about
24
694
J. Opt. Soc. Am./Vol. 71, No. 6/June 1981
Wyart et al.
B
Y
3d¹⁰⁴p-3d⁸⁴p². When we did this, application of the GLS
E
F
procedures used for the 3d94s4p configurations proved to be
important.
0
m
C
The 3d94p2 configuration is expected to lie below the ion-
ization limit in the present ions. It has a total of 28 levels, of
which 21 have J = 1/2, 3/2, 5/2 and can combine with 4p
²Pi/2,3/2. Because of strong electrostatic interactions within
C
the n = 4 shell, the 3d⁹₄p² configuration is expected to be
perturbed by the 3d⁹4s², 3d⁹4s4d, and 3d94d2 configurations,
which do not radiate to the 3d¹⁰nl levels. They show their
presence mainly by perturbing the 3d⁹4p² levels. The 3d⁹4s2
and 3dª4d² configurations are expected to be far enough from
F
B
3d⁹₄p² that their perturbations can be treated by effective
Zr
E
G
electrostatic interactions. However, 3d°4s4d is close to
3d⁹₄p² and must be specifically included in the energy matrix.
m
Our matrix thus included the 18 ordinary electrostatic and
C
spin-orbit parameters for these two interacting configurations
d
D
plus a correction of the type aL(L + 1) for the terms of the
C
subconfiguration 4p2 and a similar one for the final terms of
3d⁹4p².
From an initial set of scaled HF parameters, predicted
wavelengths and line strengths for the 3d¹⁰⁴p-3d⁹⁴p² tran-
sitions could be calculated. This led to the identification of
B
F
several strong lines of this array and also made it evident that
E
G
the levels of 3d94s4d and about 10 levels of 3d⁹₄p² would not
E
be observable with the present data. Ensuing least-squares
C
calculations were made by fixing the internal 3d°4s4d pa-
D
H
rameters at their HF values. The position of the 3d°4s4d
configuration relative to 3d⁹4p2 was fixed in such a way that
the separation between their lowest levels would equal the
value of E(3d104d)-2E(3d¹⁰⁴p) as given by the known levels
of the one-electron system. Thus all 3d94s4d parameters
B
Mo
were fixed except the 3d°4s4d-3d°4p2 configuration inter-
k m
E
G
action integral R¹(4p4p, 4s4d). Again, a GLS procedure was
C
used for fitting the 3d⁹₄p² parameters and R¹(4p4p, 4s4d).
0
D
d
H
I
The scaling factors of F²(3d4p), G¹(3d4p), G³(3d4p), S3d, and
C
R¹(4p4p, 4s4d) were assumed to be constant along the se-
quence. Scaling factors for F²(4p4p) and S4P were left un-
Fig. 1. Comparison of the spectra of Y XI, Zr XII, Nb XIII, and
constrained.
Mo XIV showing isoelectronic regularities in the region of the strongest
3d¹⁰4s-3d³4s4p transitions (capital letters), 3d¹⁰⁴p-3d⁹4p² transi-
By reducing the number of free parameters to 17, and
tions (lower-case letters), and 3d¹⁰4s-3d¹⁰⁷p transitions (Greek let-
carrying out successive line identifications and least-squares
ters). Complete designations are given in Tables 1 and 7. Lines
calculations, we could obtain values for 44 3d⁹4p² energy
marked with dots pertain to higher ionization stages in Y; two of them
levels in the four ions. The fitted and HF values of the pa-
have been classified as Y XIV.⁶
rameters for the 3d⁹₄p² configurations are given in Tables 4
and 5, respectively. Table 5 also includes the HF values for
3d⁹4s4d. In the least-squares fits to the observed levels, the
aL(L + 1) correction for the final terms of 3d⁹4p² remained
140 cm⁻¹. Compared with the independent calculations, the
undefined and was dropped. The fitted values of a for the
GLS process does not produce changes in any of the line
terms of 4p2 are given in Table 4. The final root-mean-square
identifications. Only nine lines have deviations До = Gexp
deviation of the calculated values was 200 cm⁻¹.
Tale larger than the experimental uncertainty.
The identified 3d¹⁰⁴p-3d⁸⁴p² transitions are given in Table
The 3d94s4p energy levels are listed in Table 2. The levels
1. The 3d94p2 energy levels are given in Table 6. For des-
are designated in the SLJ scheme, which
ignating the levels, no entirely satisfactory coupling scheme
proved to be the best of the several possible schemes.
could be found. We have adopted the (3d9 S₁L₁, 4p2 S₂L₂)
The fitted values of the scaling factors and parameter values
SLJ scheme, although it is not appreciably better than the
are given in Tables 3 and 4, respectively. In Table 5 we list
(3d9 S₁L₁J₁, 4p2 S₂L₂J₂) J scheme. The lack of a pure cou-
the HF values of the parameters.
pling scheme results from the presence of electrostatic and
spin-orbit terms of comparable magnitude in the Hamilto-
3d"4p-3d"4p" Transitions
nian. The labeling of levels is further complicated by the
With the strongest satellite lines accounted for by the
changing importance of these interactions along the sequence.
3d¹⁰⁴s-3d⁹4s4p transitions, we then tried to correlate the
For example, the ratio F2(4p4p)/54p decreases from 5.5 in
remaining lines with the group expected to be next in strength,
Y XI to 3.5 in Mo XIV. Therefore significant changes occur
Wyart et al.
Vol. 71, No. 6/June 1981/J. Opt. Soc. Am.
695
Table 2. Experimental Energy Levels of the 3d 4s4p Configurations of Y XI, Zr XII, Nb XIII, and Mo XIVa
YXI
Zr XII
Nb XIII
Mo XIV
Per-
Per-
Per-
Per-
J
Designation
E (cm⁻¹)
ДЕ
cent
E (cm⁻¹)
ДЕ
cent
E (cm⁻¹)
ДЕ
cent
E (cm⁻¹)
AE
cent
1/2
(2D, 3P) 4P°
1 287 540
-20
81
1 475 630
-120
77
1 674 440
50
73
1 883 400
-50
68
(2D, sp) 2pe
1 301 350
50
90
1 489 840
10
85
1 688 800
60
82
1 898 000
0
79
(2D, 3P) 4D°
1 304 450
ob
79
1 494 150
90
71
1694 450
20
63
1 905 750
140
56
(2D, 1P) 2pe
1 357 980
-90
98
1 551 210
260
97
1 754 350
-170
97
1 968 960
130
96
3/2 (2D, 3P) 4po
1 275 120
70
64
1 460 370
-80
58
1 656 110
230
52
1 861 340
90
46
(2D,3P) ⁴F°
1 283 530
60
86
1 470 100
-200
85
1 667 480
-10
84
1 874 940
-60
84
(2D,3P) 2D°
1 292 990
-30
54
1 479 960
-100
53
1 677 520
50
52
1 885 220
-50
50
(2D, SP) 2po
1 300 060
150
59
1 488 080
-40
58
1 686 760
20
57
1 895 720
-60
57
(2D,³P) ⁴D°
1 311 070
50
52
1 501 560
20
52
1 702 750
-60
52
1 914 770
-90
51
(2D, 1P) 2pe
1 343 080
-80
92
1 533 750
160
91
1734240
-180
90
1 945 620
-50
89
(2D, ¹P) 2D°
[1 372 610]
96
[1 566 430]
96
[1 770 900]
95
[1 986 080]
94
The deviations AE - Eesp- Eth are taken from the generalized least-squares treatment of the whole sequence. The percentage of the leading LS component
is given. Predicted energies for the (2D, 1P) 2Din levels are given in brackets.
b "Level value based on eyepiece measurement; not used in least-squares fit.
Table 3. Fitted Scaling Factors for the Hartree-Fock Integrals
Parameter
Y XI
Zr XII
Nb XIII
Mo XIV
Footnotes
F²(4p4p)
0.772 ± 0.014
0.769 ± 0.013
0.733 ± 0.013
0.720 ± 0.013
.
F2(3d4p)
0.987 ± 0.007
0.987
0.987
0.987
s,1
0.992 ± 0.006
0.992
0.992
0.992
6,1
G¹(3d4p)
0.983 ± 0.008
0.983
0.983
0.983
s.1
0.981 ± 0.007
0.981
0.981
0.981
6.1
G³(3d4p)
0.983
0.983
0.983
0.983
e.2
G²(3d4s)
1.012 ± 0.018
1.012
1.012
1.012
b,1
G¹(4s4p)
0.786 ± 0.001
0.789 ± 0.001
0.791
0.794
6,3
Sad
1.049 ± 0.012
1.049
1.049
1.049
s.1
1.028 ± 0.006
1.024 # 0.006
1.021
1.018
b.3
Sap
1.090 ± 0.012
1.088 ± 0.008
1.094 ± 0.007
1.095 ± 0.007
a
1.125 1 0.005
1.125
1.125
1.125
6,1
R¹(4p4p, 4a4d)
0.956 ± 0.066
0.956
0.956
0.956
e,l
. GLS fit of 3d°4p2 + 3d°4s4d.
b GLS fit of 3d°4s4p.
1 An equal value has been assumed for the four elements.
2 The same scaling factor has been assumed for G³(3d4p) and G¹(3d4p).
3 The scaling factors are constrained to be linearly dependent on the atomic number.
in the eigenvectors, as is seen in Table 6, and also in some of
if 76.928 A is used for this transition. Because of the regu-
the calculated line strengths. Our names for levels having
larity of δn* for the lower members of the np series (0.0192
leading percentages of less than 50% are assigned mainly for
for 4p, 0.0188 for 5p, and 0.0187 for 6p), we consider 76.928
use with the classified line list.
A as the best choice for 48 251/2-7p 2P3/2. The reduced in-
tensity of F in Y XI is undoubtedly caused by mixing between
Identification of the 3dⁿᵉ7р 1P° Term
the 3dᵍ(2D)4s4p(³P) 2P³/2 and 3d¹⁰⁷P 2P³/2 states, which
Comparison of the spectra in Fig. 1 shows that in Y XI line F
makes unambiguous identification of the two lines diffi-
is weaker relative to the other 3d¹⁰4s-3d³4s4p transitions and
cult.
is split into two components. The two components (76.920
In Mo XIV Curtis et al.⁸ classified lines at 53.19 ± 0.05 À and
and 76.928 A) both have the excitation character of Y XI. If
53.30 ± 0.05 A as 48 2S1/2-7p 2P3/2 and 48 251/2-7p 2Pi/2
these lines are taken as transitions to the ground state, they
transitions, respectively. These wavelengths agree with our
would involve upper levels with effective quantum numbers
present values for these lines, 53.221 ± 0.005 A and 53.335 ±
n* = 6.0737 and n* - 6.0725, respectively. As the known
0.005 A. However, it is clear from isoelectronic considerations
members of the 3d¹⁰np 2P³/2 series have effective quantum
that most of the intensity of the 53.335-Å line is due to the
numbers n*(4p) = 3.0245, n*(5p) = 4.0546, and n*(6p) =
3d¹⁰4s 4F3/2 transition. Our new value
5.0667, there is little doubt that one of these lines is 48
for the 7p 2P³/2 level, 1 878 940 cm⁻¹, is confirmed by obser-
2S1/2-7p 2P³/2. If we identify a line at 77.058 À as 4s 2S1/2-7p
vation of the 4d 2D5/2-7p 2P³/2 transition at 87.717 A.
2Pi/2, we obtain a value of dn* = n*0 = 3/2)-n*(j = 1/2) of
Our wavelengths for the 4s-7p transitions in Y XI, Zr XII,
0.0196 if 76.920 A is identified as 4s 2S1/2-7p 2P3/2 and 0.0184
Nb XIII, and Mo XIV are given in Table 7. The lines are noted
696
J. Opt. Soc. Am./Vol. 71, No. 6/June 1981
Wyart et al.
Table 4. Fitted Parameter Values (in cm⁻¹) for the 3d4s4p and
Configurations of Y XI, Zr XII, Nb XIII, and Mo XIV
Configuration
Parameter
Y XI
Zr XII
Nb XIII
Mo XIV
3d°4s4p
A
1 339 595
1 529 988
1730788
1 241 997
G²(3d4s)
19 422
20 452
21479
22 501
F2(3d4p)
53 883
57 598
61 268
64899
G¹(3d4p)
17 428
18610
19779
20935
G³(3d4p)
17362°
18 605°
19832°
21046°
G¹(4s4p)
93 059
98 402
103 703
108 974
Sad
6 959
8 103
9376
10 787
Sap
13 128
15 770
18741
22 068
3d°4p2
A
1 565 492
1774993
1 994 607
2 225 502
F2(3d4p)
53 462
57 155
60 803
64413
G¹(3d4p)
17 404
18 590
19763
20 924
G³(3d4p)
17 013
18 236
19444
20 639
F2(4p4p)
69 351
72 864
73 041
75 265
α(4p4p)
-1017
-1017
-1017
-1017
53d
7 107
8 302
9638
11 125
Sap
12684
15 214
18 184
21435
Configuration
R¹(4p4p, 4s4d)
105 857
112 338
118 640
124 790
Interaction
Fixed at HF value.
Table 5. Hartree-Fock Integrals (in cm⁻¹) for the configurations
3d 4s4p, 3d³4p², and 3d 4s4d of Y XI, Zr XII, Nb XIII, and Mo XIV
Configuration
Integral
Y XI
Zr XII
Nb XIII
Mo XIV
3d94s4p
Esv
1326636
1 519 359
1724419
1 937 001
G²(3d4s)
19 184
20 202
21216
22 226
F2(3d4p)
54 307
58 052
61751
65 410
G¹(3d4p)
17764
18 969
20 160
21 339
G³(3d4p)
17 362
18 605
19 832
21 046
G¹(4s4p)
118 392
124 758
131 028
137 217
53d
6770
7 909
9183
10 600
Sap
11 668
14 015
16 657
19613
3d°4p2
Esv
1 525 782
1 733 589
1 953 431
2 181 418
F2(3d4p)
54 193
57 937
61635
65 294
G¹(3d4p)
17698
18 904
20 097
21 277
G³(3d4p)
17 300
18 544
19772
20 987
F2(4p4p)
89810
94775
99 675
104 519
Sad
6772
7911
9184
10 601
Sep
11 640
13 985
16 624
19 579
3d°4s4d
E₈v
1 643 121
1 862 502
2 093 871
2 332 554
F2(3d4d)
46 395
50 995
55 546
60 053
F4(3d4d)
21681
24 038
26379
28 705
G°(3d4d)
15 728
17215
18673
20 105
G²(3d4d)
18 298
20210
22 099
23 966
G4(3d4d)
13 497
15 457
16 954
18 438
G²(3d4s)
19 224
20 230
21 234
22 235
G²(4s4d)
80 820
86671
92 274
97 663
53d
6780
7 920
9 193
10 610
5rd
1147
1 435
1766
2146
Configuration
R¹(4p4p, 4s4d)
110744
117 524
124 116
130 550
Interaction
as a and B in Fig. 1. The 7p energy levels are given in Table
3d⁹4s²4p 1Pi and ³Dᵢ levels of Y X, Zr XI, and Nb XII are given
8.
in Table 9. Our new measurements for these transitions in
Mo XIII are also given here. The
3d-Ap Transitions in Zn-like and Ni-like Ions
transition, expected to be weak, has not been observed.
The remaining satellite lines are the 3d104s2-3d84s24p tran-
Our measurements for the 3d¹⁰-3d⁹₄p resonance lines of
sitions in the Zn-like ions. Our identifications for the
the Ni-like ions Y XII, Zr XIII, Nb XIV, and Mo XV are given in
Wyart et al.
Vol. 71, No. 6/June 1981/J. Opt. Soc. Am.
697
Table 6. Experimental Levels of 3d°4p2 a
YXI
Zr XII
Nb XIII
Mo XIV
Per-
Per-
Per-
Per-
J
Designation
E (cm⁻¹)
ДЕ
cent
E (cm⁻¹)
ДЕ
cent
E (cm⁻¹)
ДЕ
cent
E (cm⁻¹)
ДЕ
cent
1/2 (2D, ¹D)
1 499 890
150
57
1704070
-160 57
1 918 750
180
59
2143950
40
59
(2D,3P)4D
1 506 550
-160
79
1 712 880
0 79
[1 929 750]
81
[2 157 680]
81
(2D,1D) ²P
1 516 750?
62
1 724 700?
62
[1 942 150]
62
[2 171 190]
62
(2D,³P) ²P
1 534 050
100
86
1742110
160
86
1 960 760
-10
87
2 190 700
80
88
(2D,³P)⁴P
[1 541 140]
83
1 751 810
-30
81
[1 973 850]
80
[2 207 330]
78
3/2 (2D,³P)⁴D
1 495 570?
69
1 699 310
70
67
[1 913 240]
64
[2 137 880]
62
(2D,1D) ²P
1 500 720?
66
1 704 740?
65
1 918 760?
64
2 143 940?
63
(2D,³P)2D
1 512 840
-60
42b
1 717 720
-20
46
1 932 740
70
49
2 158 460
270
51
(2D,3P) 4F
1 519 020
50
36ᶜ
1 725 880
40
40
1943180
-320
44
2 171 600
-500
46
(2D,1D) 2D
1 524 990
-40
56
1732710
-20
55
1 950 830
-30
55
2 180 320
0
54
(2D,³P)2P
1 536 320
-120
24d
1745170
-150
57
1 964 340
-170
61
2194630
-120 62
(2D,³P)⁴P
1 538 060
270
31'
[1 747 680]
46
1969260
160
45
[2 202 130]
43
(2D, 1S) 2D
[1 577 960]
86
[1 790 120]
84
[2 011 970]
82
[2 246 300]
80
5/2 (2D, 3P)
[1 484 890]
52
[1 685 980]
48
[1 896 670]
45
[2 117 650]
42
(2D,³P)2F
[1 503 800]
53
[1 707 860]
53
[1 922 230]
51
[2 147 280]
50
(2D,³P)⁴P
[1 506 180]
38
[1 710 790]
41
[1 925 540]
43
[2 151 050]
45
(2D,³P) ⁴F
[1 520 030]
28/
1 727 180
150
32
1 944 890
110
35
[2 173 560]
39
(2D,¹D) ²F
[1 522 800]
23ª
[1 730 340]
25h
[1948520]
28
[2 177 840]
31
(2D,3P)2D
1 532 560
-50
54
1 740 950
-40
53
1 960 070
140
52
2 190 210
110
51
(2D,¹D) ²F
1 542 590
-100 58
1753410
-20
56
1 974 930
60
51
2 208 210
380
47
(2D, 1S) 2D
1 561 470
40
83
1 770 980
110
80
1989710
-100
76
2220830
-160
71
The deviations AE - Eesp Eth are taken from the generalized least-squares treatment of the whole sequence. Predicted energies for unknown levels are given
in brackets. The designations are given in LS coupling with parent term of 4p2 in parentheses. The percentages of the leading eigenvector components are also
given.
Leading component, (1P) F, 49%.
. Leading component, (P) 2D, 40%.
of Leading component, ('D) 2P, 26%.
Leading component, (3P) 2P, 47%.
1 Leading component, (³P) 4P, 30%.
. Leading component, ($P) 4F. 29%.
A Leading component, (3P) 4F, 26%.
Table 7. 3d¹⁰⁴s-3d¹⁰⁷p Transitions in Y XI, Zr XII,
Table 8. Energy Levels (in cm⁻¹) of the 3d¹⁰⁷,
Nb XIII, and Mo XIV
Configurations of Y XI, Zr XII, Nb XIII, and Mo XIVa
Transition
Code
Y XI
Zr XII
Nb XIII
Mo XIV
Designation
Y XI
Zr XII
Nb XIII
Mo XIV
3d¹⁰4s 2S₁/₂-
a
76.931
67.440
59.666
53.228
3d¹⁰⁷ₚ
1 297 620
(1 479 820)
1 672 440
(1 874 730)
3d¹⁰⁷P 2Pi/2
3d¹⁰7p²P³₂
1299870
1 482 800
1676000
1 878 710
3d¹⁰4s 2S1/2-
B
77.064
67.576°
57.793
53.341ᵇ
3d¹⁰⁷P 2Pin
The values in parentheses are derived from blended lines.
. Blended with 3d¹⁰4s (2D, 3P) 3Dir.
b Blended with 3d¹⁰⁴s 251/2-3d*4s4p (2D, sp) Fin.
Table 9. 3d-4p Transitions in Ni-like and Zn-like Ions
X(A)
Int.
A(A)
Int.
X(A)
Int.
A(A)
Int.
Transition
Y XII
2r XIII
Nb XIV
Mo XV
3d¹⁰ 1So-3d⁹⁴p 3Di
72.103
80
63.234
100
55.963
100
49.914
100
1Pi
72.734
100
63.828
150
56.523
150
50.448
150
spi
73.588
5
64.538
5
57.119
5
50.956
5
Yx
Zr XI
Nb XII
Mo XIII
3d¹⁰4s2 1So-3d*4s²4p
78.706
10
68.562
5
60.332
10
53.551
10
1Pi
79.338°
100
69.161
15
60.902
20
54.101
20
Blended with 3p⁶3d⁸ 1G4-3pᵇ3d° 1F3 transition of Y XIV.
698
J. Opt. Soc. Am./Vol. 71, No. 6/June 1981
Wyart et al.
Table 9. For some lines they differ significantly from the
The improved values for Nb XIII are:
earlier values of Alexander et al.9 Our assignment of the line
at 73.588 A as 3d¹⁰ ¹S₀-3d⁹₄p 3Pi in Y XII represents a revised
58.367 (8)
58.893 (5)
59.295 (40)
59.984 (5)
line identification from that given in Ref. 9.
58.391 (20)
58.917 (3)
59.623 (20)
60.397 (10)
58.413 (10)
59.024 (5w)
59.836 (2)
J.-F. Wyart wishes to acknowledge the support of his stay
58.735 (10)
59.223 (20)
59.733 (5)
at NBS by a NATO grant. A. Ryabtsev would like to thank
W. C. Martin for generous hospitality in making possible his
REFERENCES
stay as a guest worker at NBS. This work was supported in
part by the Office of Magnetic Fusion Energy of the U.S.
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* NBS Guest Worker, on leave from Laboratoire Aime
69, 144-149 (1979).
2. J. Reader and N. Acquista, "Spectrum and energy levels of
Cotton, CNRS, France.
eleven-times ionized zirconium (Zr XII)," J. Opt. Soc. Am. 69,
+ NBS Guest Worker; permanent address, USSR Academy
1659-1662 (1979).
of Sciences, Institute for Spectroscopy, Troitsk, Moscow
3. J. Reader and N. Acquista, "Spectrum and energy levels of ten-
Region, 142092, USSR.
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(1979).
4. J. Reader and N. Acquista, "Spectrum and energy levels of
twelve-times ionized niobium (Nb XIII)," J. Opt. Soc. Am. 70,
317-321 (1980).
Note added in proof: Recent measurements in second and
5. P. G. Burkhalter, J. Reader, and R. D. Cowan, "Spectra of Mo
XIII-XVIII from a laser-produced plasma and a low-inductance
third orders have indicated systematic shifts in our wavelenths
vacuum spark," J. Opt. Soc. Am. 70, 912-919 (1980).
for Zr XII and Nb XIII. The improved values for Zr XII (in A)
6. J. Reader and A. Ryabtsev, "3p63d8-3pᵇ3d" transitions in Sr XIII,
are as follows (intensities are in parentheses):
Y XIV, Zr XV, Nb XVI, and Mo XVII," J. Opt. Soc. Am. 71, 231-237
(1981).
64.488 (20)
65.775 (10)
66.341 (2)
67.130 (30)
7. C. Froese, "Numerical solution of the Hartree-Fock equations,"
64.814 (1w)
65.910 (10)
66.608 (8)
67.209(50)
Can. J. Phys. 41, 1895-1910 (1963).
65.080 (2)
65.832 (1)
66.699 (3)
67.576 (30)
8. L. J. Curtis et al., "Energy levels and transition probabilities in
65.218 (50)
65.044 (5)
66.727 (5p)
67.774 (5)
Mo XIV," Phys. Scr. 16, 72-76 (1977).
9. E. Alexander et al., "Classification of transitions in the euv spectra
65.484 (5)
66.094 (20)
66.803 (5)
68.028 (2)
of Y IX-XIII, Zr X-XIV, Nb XI-XV, and Mo XII-XVI," J. Opt. Soc.
65.557 (3)
66.129 (10)
66.938 (3)
68.479 (15)
Am. 61, 508-514 (1971).
29
710
J. Opt. Soc. Am./Vol. 72, No. 6/June 1982
A. Ryabtsev and J. Reader
Spectra of the cobaltlike ions Sr XII, Y XIII, Zr XIV, Nb XV, and
Mo XVI
Aleksandr N. Ryabtsev* and Joseph Reader
National Bureau of Standards, Washington. D.C. 20234
Received December 19, 1981
Spectra of the cobaltlike ions Sr XII, Y XIII, Zr XIV, Nb XV, and Mo XVI have been observed by means of a low-in-
ductance vacuum spark and a 10.7-m grazing-incidence spectrograph in the region 40-95 A. For Y XIII, Zr XIV,
Nb XV, and Mo XVI more than 40 transitions of the type 3d⁹-3d⁸₄p were identified in each ion. For Sr XII about
20 such transitions were identified. The identifications were made with the aid of Hartree-Fock and least-squares
parametric calculations. New wavelengths were obtained for the 3p63d9-3p⁸3d¹⁰ transitions in these ions. The
previous analysis of Mo XVI was partially revised and extended.
The spectra of atoms of highly ionized molybdenum have
Burkhalter et al.⁷ Our present work further revises these
been of increased interest lately because of their use in con-
identifications and extends the number to 43.
nection with tokamak fusion research. Spectra of the co-
baltlike ion Mo XVI have been observed in the TFR tokamak
EXPERIMENT
in France¹ as well as in the DITE tokamak in England.²
Current studies also indicate the likely use of niobium and
The measurements were taken from spectrograms made in
zirconium in future reactors. It is thus important to obtain
connection with a recent investigation⁹ of the spectra of the
well-established line identifications for highly ionized atoms
ironlike ions Sr XIII-Mo XVII. The spectra were made on the
of these elements. In the present paper we report line iden-
10.7-m grazing-incidence spectrograph at the National Bureau
tifications and energy levels for the isoelectronic sequence of
of Standards (NBS). The grating had 1200 lines/mm. The
cobaltlike ions Sr XII, Y XIII, Zr XIV, Nb XV, and Mo XVI.
angle of incidence used for Y, Zr, Nb, and Mo was 85°. This
Ions of the Co I isoelectronic sequence have the ground
resulted in a plate factor of 0.12 A/mm at 60 A. The spectrum
configuration 3p⁶3d⁹. The first excited configuration is
of Sr was photographed at an angle of incidence of 80°. The
3p⁵3d¹⁰, which gives rise to three strong resonance transitions
plate factor was 0.17 A/mm. The spectra were excited by
at relatively long wavelengths (70 À in Mo XVI). The next
means of a low-inductance vacuum spark operating at a ca-
excited odd configuration is 3p⁶3d⁸⁴p, which gives rise to a
pacitance of 14 µF and a voltage of 10 kV.
complex group of resonance lines at somewhat shorter wave-
One set of plates was measured with the aid of a semiauto-
lengths (45 A in Mo XVI).
matic comparator at the Institute for Spectroscopy in Mos-
The 3p63d9-3p⁸³d¹⁰ transitions of Sr XII, Y XIII, Zr XIV,
cow.¹⁰ Wavelengths were calculated by using a computer
and Mo XVI were first observed by Edlén,³ although no
code that provided an approximation of the plate-correction
wavelength measurements were reported. Edlén's prelimi-
curve by a cubic polynomial. Secondary standards of wave-
nary wavelengths for these ions can be inferred from the data
length were obtained by measurements of lines in the second
in Table 27 of his review monograph4; for Sr XII, Y XIII, and
order relative to impurity lines of oxygen and fluorine as well
Zr XIV, the wavelengths may also be inferred from the level
as lines of Y-Mo in various stages of ionization. 9,11-14 A
values given in Atomic Energy Levels. In 1971, Alexander
second set of plates was measured at NBS. For this set all
et al.⁶ reported measurements for the 3p63d9-3p53d10 tran-
lines were measured in the second order. Averages of the
sitions of Y XIII-Mo XVI. New wavelengths for these tran-
wavelengths from the two sets were used for the finally
sitions in Mo XVI were given in 1980 by Burkhalter et al.⁷
adopted values.
Wavelengths for the same transitions in Sr XII were given
Intensities for the observed lines of Y-Mo were derived in
recently by Acquista and Reader.⁸
Moscow from densitometer recordings of the spectrograms
The 3d⁹-3d⁸4p transitions of Sr XII and Y XIII were first
by use of an estimated characteristic curve to represent the
observed by Edlén. The transition groups are indicated on
response of the photographic plate. For Sr XII the intensities
the spectrograms in Fig. 2 of Ref. 3 and in Fig. 49 of Ref. 4. No
were visually estimated from the photographic blackening.
wavelengths were given. Alexander et al.⁶ published wave-
The intensity of the 3d9 ²D₅/₂-3d⁸(³F)4p 2F7/2 transition in
lengths with no identifications for about 25 lines of this group
each spectrum was given a value of 1000.
in each of the ions from Y XIII to Mo XVI. Mansfield et al.²
The wavelengths, intensities, and classifications of the
used a laser-produced plasma to observe this group in Mo XVI.
3d⁹-3d⁸₄p transitions are given in Table 1. The uncertainty
They reported identifications for 25 lines. These identifi-
of the wavelengths is estimated as ±0.005 A. The present
cations were revised and extended to a total of 38 lines by
values for the 3p63d9-3p53d10 transitions are given in Table
30
A. Ryabtsev and J. Reader
Vol. 72, No. 6/June 1982/J. Opt. Soc. Am.
711
Table 1. 3d"-3d⁶₄p Transitions in Sr XII, Y XIII, Zr XIV, Nb XV, and Mo XVI
Sr XII
Y XIII
Zr XIV
Nb XV
Mo XVI
Transition
1 (A)
Int.
1 (A)
Int.
A (A)
Int.
Int.°
1 (A)
Int.
A (A)
Int.
2Ds/2-(IS) 2P3/2
60.662
20
53.847
90
116
48.138
80
43.324b
60
²Da/2-(1S)
61.303
10
54.437
20
33
48.685
30
43.837b
30
²Da/2-(1S)
62.111
30
55.190
100
130
49.399
160
44.509b
100
2D5/2-(¹G) 2G7/2
63.408
90
56.141
170
177
50.091
120
45.000h
220
2Ds/2-(3P)
63.964
30
56.585
110
104
50.451
110
45.290h
60
2D5/2-(1D) 2F7/2
64.012
60
56.597
110
44
50.435
80
45.250
30
2Ds/2-(3P) 2Ds/2
64.112
10
56.706
10
14
2D3/2-(3P)
64.272
200
56.879
260
664
50.732
250
45.553b
300
2Ds/2-(3P)
73.329
50
64.279
250
56.854
270
459
50.678
170
45.483b
220
2D₅/2⁻(³P) 4D5/2
64.469
90
56.986
220
226
50.770
240
45.545
250
2D5/2(1)
73.679
150
64.555
200
57.083
290
628
50.877
400
45.659h
300
2D3/2-(1G) 2Fs/2
73.631
250
64.569
600
57.138
700
1177
50.958
850
45.756b
700
²D₃/₂-(³P)
64.646
40
57.230
380ᶜ
200
51.055
280ᶜ
45.867
150
²D₃/₂-(³P)
64.677
40
57.230
380ᶜ
92
51.055
280
45.853ᵇ
170
2Ds/2-(3P) 4D7/2
73.772
500
64.691
600
57.241
800
659
51.038
650
45.809h
500
2D₃/²⁻(³P) 2Ds/2
73.932
50
64.825
200
57.360
320
340
51.155
450
45.938b
500
2Ds/T-(3P) 4D3/2
64.851
10
17
2D₅/2⁻(¹D) 2Ds/2
74.074
150
64.906
250
57.393
290
269
51.147
200
45.887ᵈ
200
²D₃/₂-(³P)
74.129
100
65.003
250
57.513
450
453
51.286
700c
46.043ᵇ
1000s
2F7/2
74.208
500
65.013
700
57.494
1000
1337
51.257
1300
46.024b
1600
2Ds/2-('D) 2D3/2
65.047
150
57.526
450
700
51.286
700Γ
46.043ᵇ
1000°
²D₃/?-(³P) 4D3/2
74.405
100
65.194
60
57.647
180
177
51.380
220
46.113ᵇ
300
2D3/2-(1D) 2P3/2
65.278
20
57.748
40
136
51.490
140
46.229ᵇ
220
²D₆/2⁻(¹D) 2Fs/2
65.304
90
57.715
260
242
51.419
400
46.131h
600
2Ds/2-(3F) 2D3/2
65.500
40
57.851
90
120
51.516
50
46.197
110
2D₅/2⁻(³F) 2F5/2
74.855
500
65.522
600
57.905
800
929
51.592
700
46.291b
650
²D₃/₂-(³P) 4D3/2
74.795
50
65.584
250
58.036
900
671
51.763
900
46.478h
1000ᶜ
2D3/2-(1D) 2D5/2
65.641
100
58.064
380
254
51.763
900c
46.463ᵇ
440
²D₃/²⁻(¹D)
65.667
30
2
2D₃/?-(³P) 4D₁/₂
58.095
190
91
51.828
140
46.573₫
750
2D5/T-(3F) 2G7/2
65.710
120
58.036
900°
155
51.682
300
46.352b
450
2D3/2-(1D) 2D3/2
75.056
250
65.785
400
58.201
500
637
51.908
400
46.623h
250
2Ds/r-(3P)
75.127
500
65.823
650
58.209
1000
706
51.889
700
46.573ᵈ
750°
4F7/2
75.294
250
65.847
350
58.134
500
199
51.745
350
46.378ᵇ
260
2Ds/s(³P) 4P3/2
65.939
10
58.284
70
19
51.935
80
46.592d
80
2Ds/T(3F) 4F3/2
75.427
250
65.970
150
58.247
350
158
51.849
250
46.478b
1000c
2Da/2-(1D) 2F3/2
75.400
100
66.046
40
58.395
60
77
52.045
90
46.712b
130
²Da/2-(3F)
75.687
500
66.247
250
58.534
300
255
52.145
150
46.781b
120
2D₃/2⁻(³F) 2Fs/2
66.271
100
58.588
180
197
52.228
1200ᶜ
46.877
150
2Ds/2-(3F) 2Dr/2
75.876
1000
66.390
1000
58.645
1000
1000
52.228
1200
46.841ᵇ
900
2Ds/2-(3F) 2F7/2
75.955
1000
66.449
1000
58.688
1000
491
52.258
1000
46.859
1000
²D₃/₂-(³P)
58.844
35
3
²D₃/₂-(³P) 4P5/2
66.580
40
58.902
120
114
52.527
100
47.165b
170
²D₃/²²³P) 4P3/2
66.696
40
58.978
130
69
52.573
120
47.186d
140
²D₃/2⁻(³F) 4F3/2
76.262
50
66.728
100
58.939
160
67
52.486
140
47.068ᵇ
90
2D₃/2-(³F) 4F3/2
66.845
10
59.680
40
23
²Ds/2-(3F) 4G5/2
66.914
70
59.126
190
55
52.676
190
47.262ᵈ
180
²Dыт-(³F) 4G7/2
67.074
10
59.237
40
8
52.750
80
47.302
20
2Ds/2-(3F) 4D₅/2
67.234
20
59.360
50
12
52.846
110
47.382
30
²Da/2-(3F) 4D3/2
67.335
20
59.482
15
14
²Da/2-(³F) 4F3/2
67.627
110
59.790
210
74
53.309
160
47.871ᵈ
150
2Da/2-(3F) 4G5/2
67.692
10
59.836
30
5
2Ds/2-(3F) 4D7/2
67.973
15
60.038
90
11
53.471
130
47.959ᵈ
90
Calculated from fitted values of energy parameters.
6
Present value for line given by Burkhalter et al., Ref. 7.
. Doubly classified.
Present value for line given by Burkhalter et al., Ref. 7, revised classification.
2, along with the values previously reported. The present
SPECTRUM ANALYSIS
values for Sr XII are not compared with those of Ref. 8 because
the measurements were taken from the same exposures and
The observations were interpreted by comparing the observed
thus differ only slightly.
spectra with calculated wavelengths and intensities of the five
31
712
J. Opt. Soc. Am./Vol. 72, No. 6/June 1982
A. Ryabtsev and J. Reader
Table 2. 3p⁶3d³-3p53d10 Transitions in Sr XII, Y XIII, Zr XIV, Nb XV, and Mo XVI
Sr XII
Y XIII
Zr XIV
Nb XV
Mo XVI
Transition
1 (A)a
À (A)a
1 (A)b
X(A)*
1 (A)b
À (A)
1 (A)b
1 (A)e
A (A)b
A (A)
3p⁶3d⁹ 2D3/2-3p53d10
2P₁/₂
86.413
81.610
81.604
77.249
77.245
73.273
73.315
69.596
69.580
69.589
2D5/2
2P3/2
92.029
87.394
87.382
83.196
83.181
79.374
79.357
75.869
75.861
75.863
2D3/2"
2P3/2
93.288
88.731
88.716
84.612
84.602
80.871
80.845
77.456
77.450
77.450
This work.
Alexander et al., Ref. 6.
Burkhalter et al., Ref. 7.
Table 3. Energy Levels (in cm⁻¹) of Sr XII, Y XIII, Zr XIV, Nb XV, and Mo XVIa
Configuration
Term
J
Sr XII
Y XIII
Zr XIV
Nb XV
Mo XVI
3p⁶3d⁹
2D
5/2
0
0
0
0
0
3/2
14 660
17 230
20 140
23 380
27 020
3p53d¹⁰
2p
3/2
1 086 610
1144240
1 201 990
1 259 890
1 318 070
1/2
1 171 890
1 242 570
1 314 660
1 388 140
1 463 880
3p63d84p
(³F)⁴D
7/2
(1 287 050)
1 471 170
1 665 610
1870170
2085110
(³F)⁴G
9/2
(1 294 130)
(1 478 120)
(1 672 850)
(1 877 670)
(2092710)
(³F)⁴D
5/2
(1 300 810)
1 487 340
1 684 640
1 892 290
2 110 510
(³F)⁴G
7/2
(1 304 500)
1 490 890
1 688 130
1895730
2 114 080
(³F)⁴G
5/2
(1 308 000)
1 494 480
1 691 340
1 898 400
2 115 860
(³F)⁴G
11/2
(1 307 760)
(1495300)
(1 693 740)
(1903070)
(2 123 170)
(³F)⁴F
3/2
(1 309 240)
1.495 960
1 692 640
1 899 240
2 115 970
(³F)⁴D
3/2
(1 314 560)
1 502 340
1 701 320
(1 910 980)
(2 131 480)
(³F)⁴F
9/2
(1 314 230)
(1 502 500)
(1701410)
(1911 100)
(2 131 540)
(³F)²F
7/2
1 316 570
1 504 910
1 703 930
1 913 580
2 134 060
(³F)⁴D
1/2
(1 316 930)
(1 505 990)
(1 706 010)
(1 916 450)
(2137580)
(³F)2D
5/2
1 317 940
1 506 250
1 705 180
1914680
2134880
(³F)²G
9/2
(1 324 150)
(1 513 830)
(1 715 100)
(1 927 290)
(2150740)
(³F)⁴F
5/2
1 325 860
1 515 840
1 716 820
192860
2 151 610
(³P)⁴P
3/2
(1 327 960)
1 516 560
1 715 720
1 925 490
2146290
(³F)⁴F
7/2
1 328 130
1 518 670
1 720 160
1 932 550
2 156 190
(³P)⁴P
5/2
1331080
1 519 200
1 717 920
1927180
2 147 240
(³P)⁴P
1/2
(1332740)
(1 520 560)
1 719 550
(1 928 850)
(2148770)
(³F)²G
7/2
(1 331 850)
1 521 840
1 723 070
1934910
2 157 400
(³F)²F
5/2
1 335 920
1 526 200
1 726 970
1938290
2 160 260
(³F)2D
3/2
1 335 890
1 526 720
1 728 560
1941 120
2 164 640
(¹D)²F
5/2
1 340 920
1 531 320
1 732 640
1 944 800
2 167 770
(¹D)²D
3/2
1 347 000
1 537 340
1738330
1949870
2 171 880
(¹G)²F
7/2
1 347 560
1 538 150
1739310
1 950 950
2 172 780
('D)2P
1/2
(1 348 800)
1 540 060
(1742530)
(1955360)
(2 179 420)
(¹G)²H
9/2
(1 352 680)
(1 540 680)
(1740350)
(1 950 390)
(2170640)
(1D)2D
5/2
1 350 000
1 540 680
1742380
1 955 150
2 179 270
(³P) D
1/2
(1 351 070)
(1 541 330)
1741460
1952840
2174190
(³P) D
3/2
1 351 650
1 542 000
1743210
1 955 260
2 178 580
(³P)⁴D
7/2
1 355 530
1 545 810
1 747 000
1959320
2 182 980
(1D)²P
3/2
1 357 240
1 549 100
1 751 820
1 965 510
2190160
(³P)⁺D
5/2
1 358 660
1 551 120
1 754 830
1 969 660
2195620
(³P)²P
3/2
1 363 690
1 555 670
1 758 880
1973240
2198620
(³P)2D
5/2
1 367 250
1 559 800
1 763 500
1978220
2 203 870
(¹G)²H
11/2
(1 368 780)
(1 560 220)
(1763660)
(1978120)
(2 203 340)
(1D)²F
7/2
(1368940)
1 562 210
1766880
1982750
2 209 940
(³P)2D
3/2
(1 370 640)
1 563 380
1 767 250
1982120
2 207 940
(³P)²S
1/2
(1 371 270)
1 564 120
1 767 480
1982050
2 207 240
(1G) ²F
5/2
1 372 780
1 565 960
1770290
1985780
2 212 530
(³P)⁴S
3/2
(1 375 020)
(1 568 520)
(1772530)
(1987640)
(2 213 610)
(³P)²P
1/2
(1 378 010)
1 573 120
1778260
1 994 520
2 222 270
(1G)2G
7/2
(1383560)
1 577 090
1781230
1996370
2 222 220
('G)2G
9/2
(1 385 820)
(1579410)
(1 783 860)
(1999340)
(225390)
(1S)2P
1/2
(1 429 980)
1 627 250
1 832 060
2047710
2 273 760
(1S)2P
3/2
(1 447 620)
1 648 480
1857120
2 077 400
2 308 200
Values for unobserved levels, given in parentheses, are those calculated with the fitted values of the energy parameters.
32
A. Ryabtsev and J. Reader
Vol. 72, No. 6/June 1982/J. Opt. Soc. Am.
713
ions. The calculations were made with a set of computer
Table 6. Energy Parameters and Mean Errors A (in
codes developed by the Institute of Physics of the Lithuanian
cm⁻¹) for the 3d⁸₄p Configurations of Sr XII, Y XIII,
Academy of Sciences. 15,16 The radial integrals were first
Zr XIV, Nb XV, and Mo XVI
computed by a Hartree-Fock (HF) calculation and then scaled
Param-
by factors obtained by extrapolation along the Co I isoelec-
Ion
eter
HF
Fitted
Fitted/HF
tronic sequence. 17,18
Although the observed spectra are complex and blended in
Sr XII
Eav
1 356 870
1 340 470 ± 130
some regions, the predicted isoelectronic trends yielded un-
F²(3d3d)
214 010
192 820 ± 910
0.901 ± 0.004
F4(3d3d)
136 318
116 630 ± 3480
0.856 ± 0.026
α₁(3d3d)
107 ± 40
1860
F2(3d4p)
55 593
54 830 ± 930
0.986 ± 0.017
G¹(3d4p)
18 218
7740 ± 340
0.974 ± 0.019
Zr XIV
G³(3d4p)
17 886
20 560 ± 2040
1.150 ± 0.114
13812P
4p
α(3d4p)
69 ± 56
S3d
6088
6 180 ±
90
1.015 ± 0.015
Sap
11 329
12 540 ±
230
1.107 ± 0.020
A
200
Y XIII
Eav
1 551 260
1 530 440 ±
70
11612a
1780
13p12p
(3P1"s
F²(3d3d)
224 667
204 370 : ± 610
0.910 ± 0.003
(1012F
13P128
11012
F4(3d3d)
143 263
130 100 ±
520
0.908 ± 0.004
(3PI2D
1°012'M
a,(3d3d)
71 ± 24
F²(3d4p)
59275
60 220 ± 530
1.016 ± 0.009
ENERGY (1000
(1012P
13P14D
G¹(3d4p)
19 399
19 210 ± 230
0.990 ± 0.012
11012D
G³(3d4p)
19 106
20 800 ± 1090
1.089 ± 0.057
13F120
13P/4P
α(3d4p)
32 ± 22
137120
S3d
7 144
7180 ±
70
1.005 ± 0.010
13F1°D
13F14F
S4P
13 586
15 150 ±
120
1.115 ± 0.009
1700
(3F12g
1271°C
A
240
Zr XIV
E.v
1 755 480
1731230±
60
F²(3d3d)
235 264
214 890 ±
580
0.913 ± 0.002
F4(3d3d)
150 169
136 350 ±
480
0.908 ± 0.003
a₁(3d3d)
76 ± 24
1/2
3/2
5/2
7/2
5/2
11/2
J-VALUE
F²(3d4p)
62 917
63 970 ±
450
1.017 ± 0.007
G¹(3d4p)
20 569
20 360 : ± 220
0.990 ± 0.011
Fig. 1. Structure of the 3d⁸4p configuration of Zr XIV. The calcu-
lated positions of unobserved levels are shown as dashed lines.
G³(3d4p)
20312
150 ± 1170
1.090 ± 0.058
α(3d4p)
34 ± 23
S3d
8 328
8410 ±
70
1.010 ± 0.008
Table 4. Spin-Orbit Parameters 53d (in cm⁻¹) for the
S4P
16 127
17910 ±
110
1.111 ± 0.007
3p⁶3d⁹ Configurations of Sr XII, Y XIII, Zr XIV, Nb XV,
A
240
and Mo XVI
Nb XV
Eav
1972210
1 942 790 ±
70
Ion
HF
Obs.
Obs./HF
F²(3d3d)
245 805
226 020 ±
740
0.920 ± 0.003
F4(3d3d)
157 039
143 220 ±
610
0.912 ± 0.004
Sr XII
5 836
5 864
1.005
a₁(3d3d)
66 ± 28
Y XIII
6863
6892
1.004
F²(3d4p)
66 526
67 860 ±
640
1.020 ± 0.010
Zr XIV
8016
8056
1.005
G¹(3d4p)
21 729
21 630 ± 260
0.995 ± 0.012
Nb XV
9 304
9352
1.005
G³(3d4p)
21 507
22 950 ± 1490
1.067 ± 0.069
Mo XVI
10737
10 808
1.007
α(3d4p)
45 ± 27
53d
9650
9690 ±
70
1.004 ± 0.007
S4P
18974
21 120 ±
130
1.113 ± 0.007
A
270
Table 5. Energy Parameters (in cm⁻¹) for the 3p⁵3d¹⁰
Configurations of Sr XII, Y XIII, Zr XIV, Nb XV, and
Mo XVI
Eav
2 198 910
2 165 110 ±
80
Mo XVI
F2(3d3d)
256 302
235 430 ±
760
0.919 ± 0.003
F4(3d3d)
163 880
149 560 ± 650
0.913 ± 0.004
Ion
Parameter
HF
Obs.
Obs./HF
a₁(3d3d)
51 ± 27
F²(3d4p)
70106
71 150 ± 660
1.015 ± 0.009
Sr XII
Eav
1 100 410
1 115 040
G¹(3d4p)
22879
22 810 ± 250
0.997 ± 0.011
53p
54 326
56853
1.0465
G³(3d4p)
22 692
23 710 ± 1550
1.045 ± 0.068
Y XIII
E&v
1 155 130
1 177 020
a(3d4p)
51 ± 27
Sap
62 188
65 553
1.0541
Sad
11 119
11 180 ±
70
1.005 ± 0.006
Zr XIV
Eav
1 209 140
1 239 550
540
22 150
24 690 ±
130
1.115 ± 0.006
Sap
70877
75113
1.0598
A
270
Nb XV
Eav
1 264 360
1 302 640
53p
80 448
85 500
1.0628
ambiguous classifications for all the identified lines. The
Mo XVI
Eav
1 317 920
1 366 670
identifications were greatly facilitated by the fact that the
Sap
90958
97 207
1.0687
3d⁹-3d⁸⁴p group is well isolated from lines of other ionization
714
J. Opt. Soc. Am./Vol. 72, No. 6/June 1982
A. Ryabtsev and J. Reader
stages. The identifications are supported by repetititon of
±200 cm⁻¹. The relative values within 3d⁸₄p are uncertain
the 3d9 2D fine-structure interval in the measurements.
by about ±100 cm⁻¹. The 3d° intervals were derived from
Nearly all 3d⁸₄p levels with J = 3/2 or J = 5/2 have observed
all observed pairs, with double weight given to the 3p⁶3d⁹
transitions to both of the 3d9 2D levels.
2D₅/2,3/2-3p⁵³ᵈ¹⁰ 2P3/2 pair because of its longer wave-
In general, the observed intensities compare well with the
length.
calculated values. As an example, the calculated values for
The structure of the 3d⁸₄p configuration of Zr XIV is shown
Zr XIV are shown following the observed intensities in Table
in Fig. 1. Although the levels are designated in the LS-cou-
1. The scale for the calculated values was obtained by setting
pling scheme, the coupling is far from pure. In Table 3 we
the intensity of the 3d9 ²D₅/2-3d⁸(³F)4p 2D3/2 transition equal
have given common designations to levels that derive from
to its observed value.
specific spectral lines that can be traced through the isoelec-
The energy levels derived from the wavelength measure-
tronic sequence. However, because the coupling changes
ments are given in Table 3. The uncertainty of the values of
along the sequence, for some levels it is not possible to adopt
the 3d⁸₄p levels relative to the ground term is approximately
an LS name that corresponds to the major eigenvector com-
Table 7. Percentage Compositions for the 3dᵃp Configurations of Sr XII, Zr XIV, and Mo XVI
J
Term
Percent Jj
Percentage Composition (LS)
1/2
(³F)4D
73, 62, 48% (3F2, 3/2)
74, 62, 48% (³F)4D + 19, 25, 30% (3P)4D + 6, 8, 11% (¹D)²P
(3P)⁴P
62, 66, 72% (³P₁, 1/2)
86, 84% (3P)+P + 5, 4, 2% (1D)2P + 2, 3, 5% (3P)4D
(³P)⁺D
61, 51, 51% (³P₀, 1/2)
69, 48, 50% (³P)⁴D + 12, 31, 26% (³F)⁴D + 11, 0, 12% (¹D)²P
(1D)2P
42, 47, 32% (1D2, 3/2)
42, 47, 32% (¹D)²P + 32, 19, 31% (3P)2P + 11, 2, 17% (3F)4D
(³P)²S
66, 66, 68% (3P1, 3/2)
57, 61, 61% (³P)²S + 27, 22, 19% (3P)2P + 6, 7, 8% (3P)4D
(3P)2P
60, 53, 47% (3P2, 3/2)
33, 33, 34% (³P)²P + 32, 24, 19% (³P)²S + 30, 35, 38% (¹D)²P
(1S)2P
93, 91, 88% (1So, 1/2)
91, 88% (1S)2P + 3, 3, 4% (1D)2P + 2, 3, 4% (3P)4D
3/2
(³F)⁴F
60, 55, 42% (3F2, 1/2)
27, 26, 20% (3F)4F + 37, 14, 6% (³F)⁴D + 10, 21, 26% (1D)2D
(³F)⁴D
35, 39, 31% (3F₃, 3/2)
40, 54, 50% (³F)⁺D + 13, 20, 24% (3P)4D + 7. 10, 13% (³P)⁴P
(³P)⁴P
38, 38, 30% (³P₂, 1/2)
39, 40, 33% (3P)4P + 33, 25, 19% (³F)⁴F + 14, 9. 7% (¹D)²P
(³F)2D
34, 35, 23% (3F2, 3/2)
37, 27, 16% (3F)2D + 31, 41, 40% (3F)⁴F + 23, 15, 14% (³P)⁴P
(1D)2D
31, 13, 2% (1D2, 1/2)
31, 20, 11% (1D)2D + 29, 22, 15% (³F)2D + 12, 22, 28% (³P)²P
(³P)⁴D
66, 37, 17% (³P₁, 1/2)
50, 29, 14% (3P)4D + 6, 20, 36% (³F)2D + 6, 15, 21% (1D)2D
(1D)²P
75, 57, 35% (1D2, 3/2).
61, 53, 38% (1D)2P + 19, 11, 5% (1D)2D + 3, 9, 17% (3P)2P
(3P)2P
48, 34, 17% (3P2, 3/2)
65, 52, 37% (³P)²P + 10, 16, 17% (1D)2D + 10, 13, 15% (3P)4D
(³P)2D
50, 45, 33% (³P₀, 3/2)
74, 69% (³P)2D + 12, 12, 9% (3P)4D + 3, 4, 5% (1S)2P
(3P)4S
47, 47, 47% (3P1, 3/2)
87, 82, 75% (3P)4S + 4, 5, 8% (³P)²P + 3, 4, 3% (3P)⁴P
(1S)2P
95, 93, 91% (1S₀, 3/2)
93, 91% (1S)2P + 2, 2, 2% (1D)²P + 1, 2, 2% (³P)2D
5/2
(³F)4D
59, 60, 56% (3F₃, 1/2)
66, 60% (³F)+D + 17, 19, 18% (3F) F + 7, 8, 9% (³P)4D
(³F)⁴G
62, 55, 43% (3F2, 1/2)
64, 56, 46% (³F)⁴G + 11, 15, 19% (1D)2F + 9, 9, 12% (SF)⁴F
(³F)2D
30, 29, 25% (3F₄, 3/2)
46, 41% (3F)2D + 18, 22, 26% (3F)4G + 16, 11, 7% (3F) F
(3F)⁴F
65, 69, 66% (3F₃, 3/2)
37, 35, 33% (³F)⁴F + 21, 19, 16% (³F)²F + 14, 19, 19% (³F)⁴D
(3P)4P
28, 31, 29% (3P2, 1/2)
31, 27, 20% (3P)+P + 22, 29, 32% (³F)2D + 14, 11, 10% (1D)²F
(³F)²F
48, 33, 21% (3F2, 3/2)
54, 43, 36% (³F)²F + 15, 17, 15% (¹D)²F + 6, 13, 18% (1D)2D
(1D)2F
31, 31, 34% (1D2, 1/2)
35, 26, 22% (1D)2F + 45, 38, 28% (³P)⁴P + 8, 11, 13% (3F)4G
(1D)2D
9, 17, 25% (3P2, 3/2)
21, 9% (1D)2D + 29, 29, 24% (³P)2D + 11, 18, 26% (³F)²F
(3P)4D
32, 33, 28% (1D₂, 3/2)
24, 17, 14% (³P)⁴D + 23, 27, 24% (1D)2D + 14, 22, 30% (1G)²F
(3P)2D
55, 56, 57% (3P1, 3/2)
46, 40, 36% (³P)2D + 36, 38, 40% (3P)4D + 13, 16, 18% (¹G)²F
(1G)²F
63, 53, 43% (¹G₄, 3/2)
63, 53, 43% (1G)2F + 7, 11, 16% (1D)2D + 10, 11, 11% (1D)2F
7/2
(³F)⁴D
87, 89, 91% (3Fs, 1/2)
77, 73, 69% (3F)4D + 13, 15, 16% (³F)⁴F + 5, 6, 8% (³F)²F
(SF)4G
87, 89, 91% (3F3, 1/2)
68, 66, 65% (³F)⁴G + 13, 14, 15% (3F)2G + 14, 12, 12% (³F)⁴F
(3F)2F
67, 74, 79% (3Fs, 3/2)
53, 57. 59% (³F)²F + 25, 20, 15% (SF)^F + 12, 15, 18% (³F)⁴D
(3F)⁴F
79, 86, 90% (3F₃, 3/2)
47, 52, 53% (*F)*F + 36, 28, 22% (°F)2F + 6, 9, 14% (3F)2G
(³F)²G
68, 61, 50% (3F2, 3/2)
64, 52, 36% (3F)2G + 20, 28, 37% (1D)2F + 12, 13, 12% (3F)4G
(1G)²F
29, 49, 69% (1G4, 1/2)
32, 50, 64% (1G)2F + 32, 14, 2% (1D)2F + 13, 15, 14% (³F)²G
(3P)4D
44, 51, 56% (3P2, 3/2)
44, 51, 56% (3P)4D + 43, 26, 8% (1G)²F + 1, 5, 14% (³F)²G
(1D)²F
43, 47, 48% (1D2, 3/2)
43, 48, 48% (1D)2F + 35, 33, 30% (³P)⁴D + 10, 4, 1% (1G)²F
(¹G)²G
86, 88, 88% (1G₄, 3/2)
88, 83, 77% (1G)2G + 11, 14, 17% (1G)2F + 3% (¹D)²F
9/2
(³F)⁴G
97, 98, 98% (3F₄, 1/2)
42, 40, 37% (³F)⁴G + 33, 36, 37% (³F)²G + 24, 23, 23% (³F)⁴F
(3F)⁴F
97, 98, 98% (3F₄, 3/2)
71, 71, 70% (°F)*F + 23, 25, 26% (³F)²G + 5, 3, 2% (³F)⁴G
(³F)²G
96, 98, 99% (³F₃, 3/2)
43, 37, 34% (⁸F)²G + 53, 57, 60% (3F)4G + 4, 5, 6% (3F)^F
(¹G)²H
92, 93, 94% (1G₄, 1/2)
90, 87% (¹G)²H + 7,9, 10% (1G)2G + 1, 1, 2% (³F)2G
(¹G)²G
92, 93, 94% (¹G₄, 3/2)
92, 90, 88% (1G)2G + 7, 8, 10% (¹G)²H + 1,1, 1% (³F)⁴F
11/2
(³F)⁴G
99, 99, 98% (3Fs, 3/2)
99, 99, 98% (³F)⁴G + 1, 1, 2% (1G)²H
(¹G)²H
99, 99, 98% (1G₄, 3/2)
99, 99, 98% (¹G)²H + 1, 1, 2% (³F)⁴G
34
A. Ryabtsev and J. Reader
Vol. 72, No. 6/June 1982/J. Opt. Soc. Am.
715
Table 8. Percentage Composition of the Levels Designated as 3d³(1D)4p 2P1/2 and 3d⁸(³P)4p 4D₁/2 in Sr XII,
Y XIII, Zr XIV, Nb XV, and Mo XVI
Level Designation
Percentage Composition
(1D)²P₁/₂
42, 19, 47, 40, 32% (1D)2P + 31, 36, 19, 28, 31% (3P)2P + 11, 23, 2. 10, 17% (3F)4D + 1, 13, 13, 3, 1% (3P)4D
+ 5, 2, 11, 10, 11% (³P)²S + 3, 4, 1, 2, 2% (1S)2P + 7, 3, 7, 7, 6% (3P)+P
(³P)⁴D₁/₂
69, 53, 48, 54, 50% (3P)4D + 11, 30, 0, 5, 12% (¹D)²P + 12, 5, 31, 28, 26% (³F)⁴D + 3, 7, 0, 2. 5% (³P)²S
+ 2, 4, 0, 0, 0% (3P)+P + 2, 1, 17, 8, 4% (³P)²P + 1, 0, 4, 3, 3% (¹S)²P
ponent in every ion. Because of this and the inherently im-
A point of some interest is the crossing of the (³F)²F₅/₂ and
pure coupling within the individual ions, for many levels the
(³P)⁴P₅/2 levels between Zr XIV and Nb XV. Although these
LS name is useful only as a convenient means of referring to
levels have the same J value, there is no evidence of a per-
the level.
turbation caused by their closeness in energy. A more com-
In Table 4 we compare the observed values of the spin-orbit
plicated crossing occurs for the (³P)⁴D₁/ and (1D)2P₁/ levels.
parameter S3d for the 3d⁹ configuration with those calculated
The (³P)⁴D₁/₂ level is calculated to lie above (1D)²P₁/₂ in
with the HF program of Froese-Fischer.19 In Table 5 we give
Sr XII and Y XIII but below it in Zr XIV, Nb XV, and Mo XVI.
a similar comparison for the 3p⁵3d¹⁰ configuration.
However, the eigenvectors of these two levels do not change
In Table 6 the values of the energy parameters obtained at
smoothly through the sequence. The percentage composi-
NBS from least-squares fits to the observed 3d⁸₄p levels are
tions for these two levels in all five ions are given in Table 8,
compared with the HF values. The least-squares calculations
where abrupt changes in composition are evident. In
include the parameters (3d3d) and α(3d4p) for effective
Y XIII-Mo XVI a transition to 3d9 is observed from the lower
electrostatic interactions within the 3d⁸ core and between the
of these two levels but not from the upper. Thus, in spite of
3d⁸ core and the 4p electron. The former has matrix elements
the crossing, it is always the lower of the two levels that is
α₁L₁(L₁ + 1), where L₁ is the total orbital angular momentum
observed.
of the 3d⁸ core; the latter has matrix elements aL(L + 1),
where L is the total orbital angular momentum.
The percentage compositions for Sr XII, Zr XIV, and Mo XVI
calculated with the fitted values of the parameters are given
ACKNOWLEDGMENTS
in Table 7. As was already mentioned, the average purities
A. N. Ryabtsev is grateful to the Atomic Spectroscopy Group
in the LS scheme are low. The purities in both the Jj and
of NBS, especially to W. C. Martin, V. Kaufman, and N. Ac-
the J₁l schemes are similarly low. The values, of unobserved
quista, for hospitality and invaluable assistance in using the
3d⁸₄p levels calculated with the fitted parameter values are
NBS 10.7-m grazing-incidence spectrograph. Thanks are also
given in parentheses in Table 3. Inasmuch as none of the
due to V. Viktorov for help with the computer calculations in
levels with J = 9/2 or J = 11/2 has an allowed transition to the
Moscow. This work was supported in part by the Office of
3d9 ground configuration. the values for these levels are all
magnetic Fusion Energy of the U.S. Department of Energy.
necessarily calculated. Most of the other unobserved levels
are J = 1/2 levels whose transitions to 3d° 2D3/2 are calculated
Permanent address, USSR Academy of Sciences, Institute
to be very weak. For Sr XII no J = 1/2 levels were ob-
for Spectroscopy, Troitsk, Moscow Region 142092, USSR.
served.
DISCUSSION
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36
Reprinted from Journal of the Optical Society of America, Vol. 73, page 1207, September 1983
Copyright © 1983 by the Optical Society of America and reprinted by permission of the copyright owner.
Revised 3p⁶3d⁸ 1S₀ level of Sr XIII, Y XIV, Zr XV, Nb XVI, and
Mo XVII
Joseph Reader and Aleksandr Ryabtsev*
National Bureau of Standards. Washington. D.C. 20234
Received March 12. 1983
Following an observation by Wyart et al. [Phys. Scr. 26, 141 (1982)], we have revised the position of the 3p⁶3d⁸ 'S₀
level in Sr XIII, Y XIV, Zr XV, Nb XVI, and Mo XVII and have redetermined the 3p⁶3d⁸ energy parameters in these
ions.
Recently, Reader and Ryabtsev1 analyzed the 3p⁶3d⁸-
In Table 1 we give the 3p⁶3d⁸ 1S₀-3p⁵³d⁹ 1P₁ and 3p⁶3d⁸
3p⁵3d⁹ transitions in the isoelectronic ions Sr XIII-Mo XVII.
transitions in the ions Sr XIII-Mo XVII. The
In this analysis the 3p⁶3d⁸ 1S₀ level was established by the
revised positions of the 3p⁶3d⁸ 1S₀ level in these ions are given
single transition 3p⁶3d⁸ 1Sσ-3p⁵³d⁹ 1P1. Subsequently,
in Table 2. The revision of 3p⁶3d⁸ 1S₀ in Mo XVII is due to
3p⁶3d⁹-3p⁸³d⁸⁴p transitions were analyzed in Sr XII-Mo XVI
our inclusion of the 3p⁶3d⁸ 1Sσ-3p⁵³d⁹ transition in the
by Ryabtsev and Reader² and in Y XIII-Ag XXI by Wyart et
array, which produces a slightly different average value for
al.³ In their report Wyart et al.³ noted that the parameters
the 3p⁶3d⁸ 1S₀ level.
for the 3p⁶3d⁸ core of the 3p⁶3d⁸4p configuration differed in
The revised energy parameters for the 3p⁶3d⁸ configuration
some important respects from those of the 3p⁶3d⁸ configu-
are given in Table 3. The ratios of the fitted value of F4(3d3d)
ration of the next ion. They concluded that the differences
to the Hartree-Fock (HF) value, which previously¹ varied
were due to an incorrect 3p⁶3d⁸ 1S₀ level, for the ions
from 0.844 for Sr XIII to 0.907 for Mo XVII, are now nearly
Sr XIII-Nb XVI in Ref. 1. Further, they proposed new iden-
constant through the sequence. The values of α(3d3d), which
tifications for the 3p⁶3d⁸ 1S₀-3p⁵³d⁹ 1P₁ transitions in
previously1 varied from 203 cm⁻¹ for Sr XIII to 123 cm⁻¹ for
Y XIII-Nb XVI.
Mo XVII, are also now nearly constant through the sequence.
We have reviewed our spectra :- this regard and have found
The differences between the observed level values and those
transitions of the type 3p⁶3d⁸ 1So-3p⁵³d⁹ 3D₁ that support
calculated with the revised energy parameters are given in
the proposed identifications of Wyart et al.³ A 3p⁶3d⁸
Table 4. The percentage compositions obtained with the
1Sσ-3p⁵³d⁹ transition was present in our original array
revised parmeters do not differ significantly from those of Ref.
for Mo XVII, but it was not included in Ref. 1 because of its
1 and are therefore not given here.
apparent absence in the isoelectronic spectra. On the basis
of revised calculations for the 3p⁶3d⁸ configuration we have
also revised the 3p⁶3d⁸ 1So-3p⁵³d⁹ 1P₁ identification in
Sr XIII. The lines identified as 3p⁶3d⁸ 1Sσ-3p⁵³d⁹ 1P₁
ACKNOWLEDGMENT
Y xiv-Nb XVI in Ref. 1 are actually 3p⁶3d⁷-3p⁵3d⁸ transi-
tions of the next higher stage of ionization, that is, of man-
This work was supported in part by the Office of Magnetic
ganeselike ions.4
Fusion Energy of the U.S. Department of Energy.
Table 1. 3p⁶3d⁸ 1So-3p³3d⁹ 1P₁ and 3p63d8 1Se-3p⁵³d⁹ Transitions in the Ions Sr XIII-Mo XVIIᵃ
Sr XIII
Y XIV
Zr XV
Nb XVI
Mo XVII
Transition
X(A)
Int.
X(A)
Int.
X(A)
Int.
X(A)
Int.
X(A)
Int.
3pe3d8 1Sσ-3p⁵3d⁹ 1P₁
88.915
30
84.180
40
79.830
20
75.828
15
72.092
20
3pe3d8 1So-3p⁵3d⁹
-
-
94.186
10
89.853
15
85.938b
60
82.317
10
Intensities are visual estimates of photographic blackening.
b Blended with 4p 2P3/2-6s 2S1/2 transition of Nb XIII.
Table 2. 3p63d8 1So Levels of Sr XIII-Mo XVII (in cm⁻¹)
Configuration
Term
J
Sr XIII
Y XIV
Zr XV
Nb XVI
Mo XVII
3p°3d®
is
0
136 720
146 020
155 800
166 070
176 680
0030-3941/83/091207-02$01.00
© 1983 Optical Society of America
37
1208
J. Opt. Soc. Am./Vol. 73, No. 9/September 1983
JOSA Letters
Table 3. Energy Parameters (in cm⁻¹) and Mean Errors A of Least-Squares Fits for the 3p⁶3d⁸ Configurations of
Sr XIII, Y XIV, Zr XV, Nb XVI, and Mo XVIIa
Ion
Parameter
HF
Fitted
Fitted/HF
Sr XIII
Eav
36 440
34 047 = 110
F2(3d3d)
214 978
195 749 ± 886
0.911 ± 0.004
F4(3d3d)
136981
123 012 ± 814
0.898 ± 0.006
α(3d3d)
121 ± 20
53d
6 133
6 103 ± 124
0.995 ± 0.020
A
292
Y XIV
Eav
39 578
37 084 ± 114
F2(3d3d)
225 641
206 447 ± 928
0.915 ± 0.004
F4(3d3d)
143 929
129 622 ± 856
0.901 ± 0.006
a(3d3d)
124 ± 21
53d
7196
7 127 ± 129
0.990 ± 0.018
A
304
Zr XV
Eav
42 883
40 376 ± 121
F²(3d3d)
236 241
216 969 ± 987
0.918 ± 0.004
F4(3d3d)
150 838
136 286 ± 913
0.904 ± 0.006
α(3d3d)
120 ± 22
S3d
8 388
284 ± 134
0.988 ± 0.016
A
320
Nb XVI
Eav
46430
43 937 ± 125
F²(3d3d)
246 787
227 526 ± 1027
0.922 ± 0.004
F4(3d3d)
157711
142 891 ± 957
0.906 ± 0.006
a(3d3d)
118 ± 23
S3d
9717
9 596 ± 132
0.988 ± 0.014
A
330
Mo XVII
Eav
50 238
47 730 ± 118
F²(3d3d)
257 286
238 000 ± 971
0.925 ± 0.004
F4(3d3d)
164 554
149 128 ± 914
0.906 ± 0.006
a(3d3d)
123 ± 22
53d
11 195
11 081 ± 116
0.990 ± 0.010
A
311
a The value for E ov listed in the HF column is that obtained by diagonalizing the energy matrix with the HF parameters, 3F4 level set at zero.
Table 4. Differences Observed Minus Calculated (in cm⁻¹) between Observed Level Values and Those Calculated
with the Fitted Values of the Parameters for the 3p⁶3d⁸ Configurations of Sr XIII, Y XIV, Zr XV, Nb XVI, and
Mo XVII
Configuration
J
Term
Sr XIII
Y XIV
Zr XV
Nb XVI
Mo XVII
3p⁶3d⁸
0
3P
170
110
80
0
20
is
80
80
70
70
70
1
3P
130
200
210
260
220
2
3F
210
160
120
90
0
3P
-270
-310
-310
-270
-230
ID
-360
-330
-330
-330
-290
3
3F
170
250
340
380
420
4
3F
-100
-110
-150
-180
-140
1G
-60
-50
-40
-50
-30
* Permanent address, Institute for Spectroscopy, USSR
2. A. N. Ryabtsev and J. Reader, "Spectra of the cobaltlike ions
Academy of Sciences, Troitsk, Moscow Region 142092,
Sr XII, Y XIII, Zr XIV, Nb XV, and Mo XVI," J. Opt. Soc. Am. 72,
710-716 (1982).
USSR.
3. J.-F. Wyart, M. Klapisch, J.-L. Schwob, and N. Schweitzer, "The
REFERENCES
3d°-3d⁸4p transitions in the spectra of highly-ionized elements
yttrium to silver (Y XIII-Ag XXI)," Phys. Scr. 26, 141-154
1. J. Reader and A. Ryabtsev, "3p83d*-3ph3d" transitions in Sr XIII.
(1982).
Y XIV, Zr XV, Nb XVI, and Mo XVII." J. Opt. Soc. Am. 71, 231-237
4. J.-F. Wyart, Laboratoire Aimé Cotton, C.N.R.S. II, 91405 Orsay
(1981).
Cedex, France (personal communication).
ATTACHMENT A
MEMORANDUM
On Cooperation Between the US National Bureau of Standards
and
the USSR Academy of Sciences
In accordance with the US-USSR Agreement on Cooperation in the Fields
of Science and Technology, dated July 8, 1977, the US National Bureau of
Standards and the USSR Academy of Sciences, referred to below as the
Sides, desiring to facilitate the expansion of scientific cooperation for
mutual benefit to the two Sides, have agreed as follows:
Article 1
Scientific cooperation may be conducted in the fields of thermal physics
and thermodynamics, materials science, spectroscopy, chemistry and chemical
kinetics, and cryogenic science. Other fields may be additionally included
by mutual agreement.
This cooperation will be carried out pursuant to, and within the framework
of, the US-USSR Agreement on Cooperation in the Fields of Science and
Technology.
Article 2
Such cooperation may be implemented by exchange of scientists, exchange of
scientific and technical information and documentation, joint meetings and
seminars, joint research projects, and by other means as may be mutually
agreed.
Article 3
Each Side shall designate a coordinator for determining the scientific
directions of the cooperation and for ensuring the scientific usefulness
of this cooperation.
Article 4
The Sides agree to exchange up to five scientists annually from each Side,
with a total length of stay of up to 14 man-months, for carrying out joint
research, and also to exchange up to 10 leading specialists from each
Side representing the scientific disciplines listed in Article 1 of this
Memorandum, for a total length of stay of up to 6 man-months.
Article 5
The selection of scientists described in Article 4 rests with the sending
Side, and all visits will be undertaken subject to acceptance by the
receiving Side. In addition, each Side may suggest scientists it would
like to receive from the other Side within Article 4, and each Side, insofar
as possible, will take into account these desires of the other Side.
Article 6
Exchange of scientists and other activities under this Memorandum will be
conducted on a receiving-side-pays basis, which means:
1. The receiving Side will assume the expenses for receiving
scientists and will pay:
a) per diem in the amount of 12 rubles in the USSR and, corre-
spondingly, the equivalent in dollars in the US for each day of the
visit;
b) lodging in a hotel or the provision of an apartment;
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e) expenses for automobile transportation for meeting and
seeing off;
2. Expenses for transportation to and from the main destination,
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3. Each Side will provide scientists of the other Side the oppor-
tunity to conduct scientific research work in laboratories and libraries
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Article 7
Nominations of scientists for exchange visits will be submitted to the
receiving Side no later than four months before the proposed date for
starting the visit. For each scientist nominated, the sending Side will
provide the following information: the full name of the scientist, date
and place of birth, education and academic degrees, place of work, scien-
tific speciality, a list of the main scientific works and publications, the
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knowledge of foreign languages, topics of lectures that could be delivered
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Article 8
The Receiving Side will respond to this nomination no later than three
months after its receipt. If the nomination is acceptable, the receiving
Side will inform the sending Side of a possible date of arrival of the
scientist in the country and will give its agreement to the program or
will propose alternatives to the program.
After receiving the consent of the receiving Side to accept a given scien-
tist, the sending Side shall inform the receiving Side by telegram or
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Article 9
The receiving Side will facilitate the timely receipt of visas by the
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Article 10
The National Bureau of Standards authorizes its Office of International
Relations, and the USSR Academy of Sciences authorizes its Foreign Relations
Department, to conduct administrative affairs in connection with this
cooperation.
Article 11
This Memorandum shaT1 enter into force upon signature by both Sides and
shall remain in force for five years. Additions and modifications may be
made to it, and its period of validity extended, by mutual agreement of
the Sides, and with the concurrence of the Executive Agents designated in
Article VII of the US-USSR Agreement on Cooperation in the Fields of
Science and Technology.
DONE at Moscow this 13th day of December, 1978, in duplicate, in the
English and Russian languages, both equally authentic.
For the US National Bureau
For the USSR Academy
of Standards
of Sciences
I Jimbles.
Security
Director