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**** ESF Programme ****
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**** RELATIVISTIC EFFECTS IN HEAVY ELEMENT CHEMISTRY ****
**** AND PHYSICS ****
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Newsletter No. 8 (23 August 1994)
______________________________________________________________
Editor: Bernd Hess, hess@rs9.thch.uni-bonn.de
Tel. 49-228-732920
FAX 49-228-732251
______________________________________________________________
The programme 'Relativistic Effects in Heavy-Element Chemistry and Physics'
('REHE') has been initiated by the European Science
Foundation in November 1992 and it is expected to run for 5 years, i.e.
from 1993 through 1997. The programme is intended to strengthen the in-
dicated "field" and to facilitate interactions between European scientists
concerned with related topics.
The 'Steering Committee' of the programme has at present the following
members:
E. J. Baerends (Amsterdam)
J.P. Desclaux (Grenoble)
K. Faegri (Oslo)
I.P. Grant (Oxford)
B. Hess (Bonn, Vice-Chairman)
H. U. Karow (ESF)
J. Karwowski (Torun)
P. Pyykko (Helsinki, Chairman)
K. Schwarz (Vienna)
A. Sgamellotti (Perugia).
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--- E D I T O R I A L
This time, the newsletter has been delayed for a few days because I
wanted to include report on the Lanthanide workshop and the announcement
of the study centre in December.
I am using a new mailer; I apologize for delay and multiply delivered
mail and hope the procedure will stabilize after a few tries ...
Please send material for the forthcoming newsletter to my attention,
hess@rs9.thch.uni-bonn.de
The newsletter will be sent out every second month around the 10th day
of the month. Contributions should arrive in Bonn until the end of the
preceding month.
The next newsletter (#9) is scheduled for Beginning of October, 1994.
Please send your contributions until End of September 1994.
Please send material >by e/mail< that enables us to fill the
following topics in forthcoming newsletters
================================================================================
--- F E L L O W S H I P S
In the framework of the REHE programme, there is support available
for visits of doctoral students and also for senior scientists at
institutions in a foreign partner country. This support covers visits
lasting 2-4 months ("long-term visits") which will give the holders
time to acclimatize to the methods used in the host laboratory as well as
short visits ("short-term visits") of only a few days.
Please send a short application detailing the project, the names of the
scientists involved and the aproximate date and duration of the visit
to either Pekka Pyykko or Bernd Hess. Please refer to REHE newsletter #7
for details.
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--- R E S E A R C H N E W S AND R E L A T E D I N F O R M A T I O N
Summaries of recent research or comments to it (up to 1 page),
which are of general interest to the 'REHE' community, may
be submitted by any colleague preferrably by E-mail to my attention.
[no material for this section in the current newsletter]
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--- C O N F E R E N C E N E W S
'Conference News' (in general they should NOT overrun about 1 page)
may be provided by organizers or their scientific secretaries. --
For meetings and workshops supported by ESF the submission of such
a report is a m u s t . To facilitate my job the reports should
be forwarded to my attention via E-mail.
Also please send information about conferences that might be of interest
for the members of the REHE community.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[first announcement of study centre on Relativity and Pseudopotentials]
=======================================================================
REHE study center on Relativity and Pseudopotentials
to be held in Helsinki (Finland)
on December 12 - December 16 1994
=======================================================================
The objectives of this study center are to give both a detailed
theoretical description of effective core pseudopotential methods and
to allow participants to test, hands on, the performance of different
approaches (pseudopotentials, model potentials, spin-orbit coupling)
with different Quantum Chemistry packages. Morning sessions will
be devoted to lectures and afternoon sessions to some pratical
applications to selected cases. Additionally , there will be a
poster session and a final discussion in which participants will
be asked to present their current work or perspectives related to
pseudopotentials and/or relativity.
It is to be clearly understood that this workshop is directed to
researchers already involved in Computational Quantum Chemistry and a
basic knowledge of it (including Hartree-Fock approximation, basic
configuration interaction technics) will be required. The main
clientele for which the study centre is being planned , are the Estern
and Central European scientists.
Applications which should include a curriculum vitae and a list of
publications have to be sent to:
Jean-Louis Heully
Laboratoire de Physique Quantique
Universite Paul Sabatier, 118, route de Narbonne
31062 TOULOUSE CEDEX, FRANCE
Tel 61 55 68 33
Fax 61 55 60 65
e-mail heully@pqthp2.ups-tlse.fr}
Deadline for applications is October 1 and information on by
acceptance will be send to participants on October 1, 1994.
Scientific programme (tentative)
Monday 12 :
Atomic relativistic effects (J.L. Heully)
Relativistic effects (P.Pyykko)
Tuesday 13 :
Pseudopotentials (J.P. Daudey)
Spin-Orbit Coupling (C. Marian)
Energy adapted pseudopotentials (M. Dolg)
Wednesday 14 :
Model potentials (U. Wahlgren)
Spin-Orbit Coupling (C. Teichteil)
Thursday 15 :
Pseudopotentials (J.P. Daudey)
Model Potentials (U. Wahlgren)
Lanthanides and Actinides (M. Dolg)
Friday 16 :
Beyond frozen-core approximations:
Core-valence effects (J.P. Daudey)
General Discussion on Specific Scientific projects
Lecturers :
J.P. Daudey, University of Toulouse, France
M. Dolg , Max Planck Institute, Dresden
J.L. Heully, University of Toulouse, France
Ch. Marian, University of Bonn, Germany
U. Wahlgren, University of Stockholm, Sweden
P.Pyykko, University of Helsinski, Finland
Ch. Teichteil, University of Toulouse, France
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[report on the ESF workshop on PNC; communicated by A.M. Martensson-Pendrill]
P and T-violating properties in atoms and molecules
ESF Workshop within the Programme on
RELATIVISTIC EFFECTS IN HEAVY ELEMENT CHEMISTRY AND PHYSICS
Oxford 7-10 april 1994
Molecular calculations are required to interprete experiments searching
for violations of symmetry under parity and time reversal in diatomic
molecules. The atomic calculations have seen considerable progress (see
e.g. Blundell et al., Theor. Chim. Acta 80, 257 (1991))
and during a few days in April about thirty scientists met in Oxford to
discuss possiblities for molecular calculations and problems that may be
encountered.
Ed Hinds (ehinds@yalevm.ycc.yale.edu) gave an introductory review of
experiments (Cho et al., Phys. Rev. Lett. 63, 2559 (1989),
Hinds and Sandars, Phys. Rev. A 21, 480 (1980) ) on the
diamagnetic molecule TlF (Hinds and Sandars, Phys. Rev. A 21, 480 (1980)),
searching primarily for possible >nuclear< electric dipole moments (EDM)
and P and T violating interactions of
tensor-pseudotensor type (see e.g. Eq (10) in my contribution in
>>Methods in Computational Chemistry<<, ed. S. Wilson (Plenum Press, New
York, 1992), Vol. 5, p. 99 ) The upper limits obtained from experiments
for TlF for these interactions, are among the lowest available. Ed
Hinds also presented plans for future experiments on YbF, with the
intention of lowering the upper limits for a possible >electron<
EDM and a scalar P and T violating interaction (Eq. (9) in the same
paper). He also emphasized that the atomic/molecular experiments give
information not only competitive with but also complementary to that
obtained from limits for the neutron EDM.
Several groups had responded to the challenge of these large-scale
molecular calculations
and many also reported preliminary wavefunctions for TlF. Nevertheless,
J\"urgen Hinze predicted that it will be several years before the >ab initio<
methods will be able to give better results than those
presented by the S:t Petersburg group
using Generalized Relativistic Effective Core- Polarization methods
(see e.g. Titov et al, Chem. Phys. Lett. 185, 330 (1991)).
Since these calculations are difficult, it will be important to have
critical tests assuring the reliability of the results obtained
(although, as long as only limits are obtained, but no effect
observed, results accurate to within a factor of 2, should be adequate).
All effects studied get their main contributions from regions within or
close to the nucleus. It would the seem worthwhile to calculate
measured properties, like magnetic and electric hyperfine structure
(hfs), that also test this part of the wavefunction. It was also
suggested that the magnetic hfs, which involves a product of the upper
and lower component of the relativistic wavefunction would be a
sensitive test of the accuracy of the basis set constructed using the
kintetic balance approach. Concerning electric hfs, most critical test
will of course be performed where the nuclear quadrupole moment is known
independently, as compiled by
Pyykk\"o and Li, (Nuclear quadrupole moments, Report HUKI 1-92, ISSN
0784-0365 (1992))
Since the effects arise close to or within the nucleus, they are all
sensitive mainly to the orbital normalization at the origin and all
operators can be related by using the orbital behaviour at small $r$.
(O. Sushkov et al., Sov. Phys. JETP 60, 873 (1984)).
This can of course be used for testing the
calculations, but also to choose the most convenient operator for the
evaluation.
The question arose on what accuracy is required for the energies in
order to obtain sufficient accuracy for P and T violating properties.
This probably depends on the methods used in the calculations, since the
parts of the wavefunction accounting for the disired effect, in general
have very little effect on the energy. However, we note that in
investigations of hyperfine structure, using variational wavefunctions,
it has been found that nearly all of the correlation energy must be
obtained (Carlsson et al. Phys. Rev. A 46, 2420 (1992),
Bauschlicher, J. Chem. Phys. 92, 518 (1990)).
The electric field at the nucleus (i.e. its average over the nuclear
charge distribution) must vanish, since the nucleus remains stationary
(Schiff, Phys. Rev. 132, 2194 (1963)) and this should also hold
for the calculated wavefunctions according to the "Hellman-Feynman"
theorem , although this may not be the case for calculations using
limited basis sets. We suggested that model calculations, even
non-relativistic, for lighter systems, such as BF, might be useful for
examination of the requirements to get this cancellation.
In addition to discussions concerning calculations for TlF and
YbF, we also had talks on related subjects and we mention here a few:
Parity non-conservation (PNC) >without< accompanying T violation
has observed and the combined theoretical
(Blundell et al., Phys. Rev. D 45, 1602 (1992)) and
experimental (Noecker et al., Phys. Rev. Lett. 65, 310 (1988))
accuracy for Cs is sufficient to demand calculations also of small corrections. The results of these experiments are usually expressed in terms of a
"weak charge" (Bouchiat and Bouchiat, Phys. Lett. 48B, 111 (1974)).
Pat Sandars introduced a new parameter
$P_W= \sqrt 2 M_Z^2G_F/ \pi \alpha Q_W$,
to describe which is found be
largely independent of the weak mixing angle, $\theta _W $ and thus displays
more clearly the sensitivity to new physics of atomic PNC experiments
(Lynn and Sandars, J. Phys. B 27, 1469 (1994)).
For isotope dependent PNC effects, the standard parametrization is,
however, found to be a better choice. Jessica James described the
dependence of the observed PNC on the nuclear distribution
(Pollock et al., Phys. Rev. C 46, 2587 (1992)) in terms of nuclear moments,
found to describe accurately a variety of nuclear models.
Sergey Porsev presented calculations of quadrupole toroidal moments
of positronium. Yulik Khriplovich presented calculations of anapole
moments for heavy atoms. A-M Pendrill showed how
atomic structure calculations can be used to extract information
about nuclear charge and magnetic moment distributions from
experimental data, with applications to Tl.
We would like to thank the European Science Foundation for support
through the program "Relativistic Effects in Heavy Element Chemistry and
Physics". Further, we would like to thank Keble College and the Nuclear
Physics Institute for providing the setting for a workshop
made very enjoyable through the lively discussion by all the
participants.
Participants
The 32 participants included 10 full professors, 13 other senior
scientists, 6 post-docs and 3 graduate students. Most of the
participants came from Germany, Great Britain and Russia, each
represented by 6 scientists, Norway, Sweden and the U.S. were
represented by 3 scientists each, and the other participants came from
Denmark, Finland, France, Greece and Israel.
G\"oteborg and Oxford, July 1994
Jessica James and Ann-Marie M{\aa}rtensson-Pendrill
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[report on REHE workshop in Helsinki, Finland, 8-9 August 1994,
Chairman: M. Dolg (Stuttgart); communicated by M. Dolg]
"Electronic Structure Methods for Lanthanides and Actinides"
The ESF workshop on Electronic Structure Methods for Lanthanides and
Actinides was held 8-9 August in Helsinki as a satellite meeting to the
2nd International Conference on f-Elements. The meeting took place
at an institute located on a peninsula 15 km outside of Helsinki. The
pleasant surroundings gave opportunity for walks at the seashore,
swimming, sauna and informal discussions.
The workshop was attended by 28 participants:
Brasil 1, Canada 1, Finland 2, France 2, Germany 10, Israel 1,
Lesotho 1, Lithuania 1, New Zealand 1, Poland 1, Russia 3, USA 4.
20 participants gave 20 or 40 minutes oral presentations of their work;
after each talk 10 minutes were reserved for discussion:
G. Malli: Dirac-Hartree-Fock calculations
A. J. Mohanty: Dirac-Hartree-Fock calculations on parallel computers
U. Kaldor: Relativistic Coupled-Cluster Calculations, application to atoms
J. Hinze: numerical methods for atoms and molecules
R. M. Pitzer: spin-orbit configuration interaction, application to U@C28 and
actinocenes
M. Dolg: pseudopotentials for lanthanides, application to CeO and Ce(COT)2
W. Kuechle: pseudopotentials for actinides, application to ThO and Th(COT)2
N. Roesch: INDO for lanthanides and actinides
S. V. Vlasov: relativistic density functional band struture calculations
P. Fulde: heavy fermion systems
M. Richter: 4-component LCAO scheme for solids using a squared Dirac-operator
B. Johansson: relativistic effects on solid state properties, LMTO calculations
G. Liu: ground state splittings of S-state ions like Gd(3+) 4f7 8S
M. F. Reid: correlation effects in f-f transition intensities
V. S. Mironov: crystal field calculations for actinide compounds
C. Heinemann: experimental and theoretical investigation of lanthanide cations
N. Edelstein: optical spectroscopy of f-element compounds
G. F. de Sa: extension of the AM1 method to lanthanide complexes
Z. Rudzikas: new methods to deal with vector coupling in f-shells
P. Pyykkoe: equatorial coordination and bond lengths of uranyl
A poster session was held on monday evening to give all participants
the opportunity to present their work.
It might be interesting to hear that relativistic electronic structure
calculations on lanthanide compounds are also performed in chemical industry
(D. Suelzle, Schering, Berlin).
As seen from the organizer's side the workshop was succesful.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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--- P O S I T I O N S available
[no material for this section in the current newsletter]
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--- P O S I T I O N S sought
[no material for this section in the current newsletter]
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--- G O S S I P
News about people visiting foreign laboratories, which could eventually
faciliate invitations by a nearby lab.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Dr. J. E. Sienkiewicz is visiting Prof. I. P. Grant in Oxford, from 9 July
to 8 October 94, to work on the relativistic CI approach to electron
scattering from atoms.
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--- ADDRESS LIST
The next address list will be provided with newsletter no. 10
In order to join the REHE mailing list, please complete the form below
and send it back per e-mail to hess@rs9.thch.uni-bonn.de
>>> PLEASE include TEL, FAX, E-MAIL <<<
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End of REHE Newsletter No. 8