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**** ESF Programme ****
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**** RELATIVISTIC EFFECTS IN HEAVY ELEMENT CHEMISTRY ****
**** AND PHYSICS ****
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Newsletter No. 24 (April 28, 1997)
______________________________________________________________
Editor: Bernd Hess, hess@uni-bonn.de
Tel. 49-228-732920
FAX 49-228-732551
______________________________________________________________
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. Daudey (Toulouse)
K. Faegri (Oslo)
I.P. Grant (Oxford)
B. Hess (Bonn, Vice-Chairman)
J. Karwowski (Torun)
P. Pyykko (Helsinki, Chairman)
K. Schwarz (Vienna)
A. Sgamellotti (Perugia)
C. Werner (ESF).
================================================================================
--- E D I T O R I A L
Please send material for the forthcoming newsletter to my attention,
hess@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 (#25) is scheduled for June 1997.
Please send material >by e/mail< that enables us to fill the
following topics in forthcoming newsletters
All REHE newsletters are available on www under URL
http://pcgate.thch.uni-bonn.de/tc/hess/esf/nl.html
see also the URL of the European Science Foundation
http://www.esf.c-strasbourg.fr
================================================================================
--- 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 #16
for details.
Please indicate >who wants to go >when >where, >what shall be done and
>how much money (in FRF) is required.
As a rule, the steering committee members will decide on the applications
on occation of ther meetings.
Applications for visits that require decision in the interim time between
steering committee meetings may still be handled by means of consultation
within the steering group.
After the journey, a short report about the scientific accomplishments
is required. Please send a version by e-mail in a form suitable for
publication in a REHE newsletter to hess@uni-bonn.de
Should the planned dates of your stay change for any reason, you are
requested to notify the Chairman and the Vice-Chairman (preferrably by
e-mail) as soon as possible with a copy to the ESF.
================================================================================
--- 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.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
NIST is building an on-line atomic database which is of interest for the REHE
community. Here I enclose some information from a letter by Yong-Ki Kim
on this database:
[communicated by Yong-Ki Kim]
March 25, 1997
...
Some part of the database is available on the internet by logging
into http://physics.nist.gov, and choosing "physical
reference data." For instance, an extensive bibliography
for atomic transition probabilities is available, along
with fundamental constants and some atomic and molecular
spectra. Work is in progress to put an "updated version"
of Charlotte Moore's Atomic Energy Levels, though it is
not yet available for public view.
...
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[communicated by Ian P. Grant]
Report on a visit by J. Biero\'{n} (Krakow) to I. P. Grant (Oxford)
17.09.96--12.10.96
The work carried out during this visit was in two parts. The first
involved a thorough review of the structure of the GRASP multiconfigurational
relativistic atomic structure code to decide how best to modify the
system the better to study medium to large atoms. Basic features of
an efficient parallel angular coefficient package were identified.
Major computational savings in the construction of the coulomb and
exchange potentials of the multiconfigurational Dirac-Fock model, and
of the full energy expression, in a parallel-processing environment are
expected from the identification of classes of terms which have a
common angular structure. Dr. Biero\'{n} proposes to elaborate these
ideas in a major revision of GRASP in Krakow, and we intend to
collaborate further on this project.
The second part of the work involved a test of the recently
developed GRASP92 package by evaluating the effects of relativity and
electron correlation on the hyperfine interaction constants of several
states of the Sc II ion. A paper is nearly ready for submission to
Physical Review A. A similar calculation has also been performed to
evaluate the experimentally known quadrupole hyperfine constant of the
unstable (64.1 hour) Y$^{90}$ isotope. A paper is in preparation for
Zeitschrift f\"{u}r Physik.
I. P. Grant,
Mathematical Institute, Oxford
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[communicated by J. P. Daudey]
MULTIPARTITIONING PERTURBATION THEORY IN RELATIVISTIC
CALCULATIONS ON HEAVY ELEMENT COMPOUNDS
A quantitative description of low-lying electronic
states of molecules containing heavy transition or coinage
metal atoms requires to combine a relativistic treatment
with highly accurate account for correlation effects. In most
cases when the correlation problem is the main bottleneck, the
use of two-step methods which treat the correlation without
spin-orbit coupling in non-relativistic symmetries appears to be
preferable [1].
We put forward a new approach to correlation relativistic
electron structure calculations via constructing a relativistic
effective Hamiltonian within a restricted model space spanned
by several multiconfigurational wavefunctions. Scalar relativistic
effects are incorporated by employing average relativistic core
pseudopotentials. The correlation contributions arising from
coupling with the outer space are calculated by means of the
multi-partitioning many-body perturbation theory (MPPT)
[2] restricted to second order. The spin-orbit interactions
are taken into account at first order using the spin-orbit
pseudopotential technique [3].
This approach is closely related to the CIPSO method [3]
employing the conventional (single-partitioning) multireference
perturbation theory. The main advantages of using the MPPT
technique for correlation treatment consist in a strict size
consistency of the results provided that the basis multiconfi-
gurational functions are generated as solutions of complete-
active-space CI problem (otherwise, at least a good approximative
size-consistency and strict "weak" separability are guaranteed)
and numerical stability. A high performance of this technique in
non-relativistic calculations of light transition and coinage
element compounds has yet been demonstrated [4]. Low computational
cost is ensured by using the recently developped diagrammatic MPPT
formulation.
Test calculations on the ground and excited states of
the AuH molecule have been performed, using the pseudopotentials
from [5] and explicitely correlating 20 outermost electrons.
Analogous calculations on (111)H (where (111) stands for eka-gold),
AuO, (111)O are to be carried out in the nearest future.
This work results from collaboration of A.Z., Ch.Teichteil
and L.Maron (Universite P.Sabatier, Toulouse).
References
[1] M.Dolg, H.Stoll, H.J.Flad, H.Preuss, J.Chem.Phys. 97 (1992)
1662
[2] A.Zaitsevskii, J.P.Malrieu, Chem.Phys.Lett. 250 (1996) 366
[3] Ch.Teichteil, F.Spiegelmann, Chem.Phys. 81 (1983) 283
[4] A.Zaitsevskii, J.P.Malrieu, Theor.Chim.Acta (1997) in press
[5] D.Andrae, U.Haussermann, M.Dolg, H.Stoll, H.Preuss,
Theor.Chim.Acta 77 (1990) 123
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[communicated by B. A. Hess]
Report on REHE scholarship of Elvira Romera (University of Granada)
From September 23, 1996 to November 23, 1996, Elvira Romera from the
Departamento de Fisica Moderna of the University of Granada visited
Bernd Hess' group at the University of Bonn as a REHE scholar.
The project set out to calculate properties of halogen atoms in the ground
state (J=3/2) and the first excited state (J=1/2), which result as a
fine-structure pair from the same non-relativistic configuration.
In previous work [Samzow and Hess, Chem. Phys. Lett. 184 (1991) 491] it had
been found that the fine-structure splitting of the bromine atom is very
much dependent on the orbital basis used for a configuration-interaction
treatment of the correlation. Moreover, the states in question are important
from an experimental point of view, because the transition moment for the
3/2 -> 1/2 transition of the iodine atom was experimentally uncertain until
very recently [Ha, He, Pochert, Quack, Ranz, Seyfang and Thanopulos,
Ber. Bunsenges. Phys. Chem. 99 (1995) 384].
The goal of our work was the calculation of the fine-structure splitting of the
ground-state systems of the bromine and iodine atoms and the moment for the
transition between the fine-structure levels, in particular the influence
of electron correlation on these quantities. We are using the GRASP92 program as
well as CASSCF/CI programs based on the Douglas-Kroll-transformed relativistic
Hamiltonian.
While a final picture has not yet obtained so far, it has been found that,
apart from substantial core polarization, a correlation of the semi-core
of d symmetry is important for the electronic properties of the states in
question.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[communicated by J. Noffke]
Relativistic effects in magnetic interlayer coupling
J.~Noffke
Institut f\"ur Theoretische Physik, TU Clausthal
Leibnizstra{\ss}e 10, D-38678 Clausthal-Zellerfeld, Germany
R.~Podloucky
Institut f\"ur Physikalische Chemie der Universit\"at Wien,
Liechtensteinstra{\ss}e 22a/1/3, A-1090 Wien, Austria
and
W. Kara{\`s}\\
Academica of Mining and Metallurgy (AGH) Krak\`ow
Zaklad Fizyki Cia{\l}a St., 30-059 Krak\`ow, Poland
The aim of that project has been the development of a computer
program to treat magnetic coupling of layers and surface
magnetic anisotropies as key quantities for device application in an
accurate and consistent approach. Therefore, the inclusion of all
relativistic effects, especially the spin-orbit coupling, has been one
of the main points. The ab-initio calculations are based on the density
functional theory of Hohenberg, Kohn and Sham [P.~Hohenberg and W.~Kohn,
Phys. Rev. {\bf 136}, B 864 (1964), W.~Kohn and L.~J.~Sham, Phys. Rev.
{\bf 140}, A 1133 (1965).] which maps the many--body problem for the electrons
onto a single--particle description. This consists in
Dirac--type one particle equations which have to be solved
self--consistently. For that we decided to extend a relativistically
generalized version of the Full Potential Linearized Augmented Plane Wave
(FLAPW-)method [E.~Wimmer, H.~Krakauer, M.~Weinert and A.~J.~Freeman,
Phys. Rev. B {\bf 24}, 864 (1981)] which is one of the most precise ab-initio
methods.
The first 3-days meeting in December 1994 in Vienna already showed that
the calculation of such tiny effects like the magnetic anisotropy
energy (of the order of $10^{-4} eV$ for surfaces) does not only require
a very accurate method for the determination of the electronic and
magnetic structure but should also deliver the relaxation - at least
the normal components - of the surface layers. The respective energy
contributions may be in the order of magnitude of the effect of spin-orbit
coupling. That is, one should do a lot of self-consistent calculations
determining the respective total energy, looking for a minimum with
respect to the atomic positions. Since those iterations are very
time-consuming we decided to first of all develop a method to determine the
forces on the atoms and include that in the total program package.
The discussion on how to include the spin-orbit coupling lead to the
conclusion that only a total revision of the program package of the Vienna
Podloucky-group can be the basis of our research activities. The
Clausthal FLAPW-code had been developed in a computer environment with
only little resources in computer time and memory, also that parts of
the package refering to the spin-orbit coupling and the calculation
of the magnetic anisotropy
[W. Kara\`s, J. Noffke and L. Fritsche, Journal de chimie physique
{\bf 86}, 861 (1989)]. The new program should be
designed in such a manner that for elements where the spin-orbit
coupling leads to neglectable density (and therefore potential)
changes it should be possible to simulate
different magnetization directions by respective rotations of the
wavefunction (especially of the coefficients for the angular momenta
expansion inside the atomic spheres). Thus, there would be necessary only one
time-consuming determination of the lattice positions consisting of a
couple of self-consistent iterations, each with the calculation of
the forces on the atoms. Of course, the symmetry of the respective
two-dimensional Brillouinzone has to be taken into account, the
irrducible part of which depends on the magnetization axis. The
wavefunction for the different parts of the surface
Brillouinzone is also available by proper rotations of the coefficients
of the angular momenta expansion. The anologous method is to transform
the respective matrix-elements.
An important aspect for the hyperfine field and
M\"ossbauer-spectroscopy is the influence
of different approximations on the wavefunction in the near of the
nucleus which has been studied by Kara\'s (to be published).
A one-week stay of R.Podloucky in Clausthal and a short meeting in
Vienna have been used to define common interfaces and to decide who
should be reponsible for the maintainance of the different
parts of the program. As a further outcome of the discussions it
seemed to be indispensable to collaborate with St.~Bl\"ugel
(KFA J\"ulich), who is well-experienced with calculations for
ultra-thin magnetic films. That should guarantee a stable
and a trustworthy basis to tackle the hardest problems of a
relativistic treatment of magnetically ordered surfaces.
We thank REHE for financial support for the meetings, which weren't
possible otherwise.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
================================================================================
--- 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.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[communicated by K. Schwarz]
DFT97
7th International Conference on the Applications of
Density Functional Theory in Chemistry and Physics
Vienna, September 2-6, 1997
Chairman: K.Schwarz
Scope:
======
This four-day conference will bring together scientists interested in DFT,
the basic aspects of theory, methodological aspects, program developments
and applications in chemistry, biochemistry and physics.
The conference will be held at the "TU Wien" and will feature invited talks,
posters and panel discussions. It will begin in the evening of Tuesday,
Sept.2, with registration and a reception and ends on Saturday, September
6, 1997.
International Scientific Committee
R.Ahlrichs (Univ.Karlsruhe, D)
R.Car (IRMMA Lausanne, CH)
P.J.Durham (Daresbury, UK)
P.Fantucci (Univ.Milano, Italy)
A.Goursot (ENSC Montpellier, F)
W.Kohn (Univ.California, Santa Barbara, USA)
R.G.Parr (Univ.North Carolina, Chappel Hill, USA
D.Salahub (Univ.Montreal, CDN)
P.Siegbahn (Univ.Stockholm, Sweden)
Local Organizing Committee
P.Blaha (TU Vienna)
J.Hafner (TU Vienna)
P.Herzig (Univ.Vienna)
H.Lischka (Univ.Vienna)
J.Luitz (TU Vienna)
P.Mohn (TU Vienna)
E.Nusterer (TU Vienna)
K.Schwarz (TU Vienna) Chairman
P.Weinberger (TU Vienna)
Continouly updated information can be found on the Web page:
http://www.tuwien.ac.at/theochem/dft97/
E-mail:
=======
dft97@tuwien.ac.at
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[communicated by Bernd A. Hess]
Research Conference on
Relativistic Effects on Structure, Dynamics and Spectroscopy
Chairman's report on the scientific programme
The third Euroconference in the REHE series took place from March 8, 1997
to March 13, 1997 in the Hotel Alixares del Generalife in Granada, Spain.
The 71 participants who attended the conference came from from 23 countries.
The programme comprised 23 lectures, and 62 posters were displayed and
discussed in two poster sessions.
In contrast to the earlier conferences (de Haan 1993 and Il Ciocco 1995),
no financial support from the Euroconferences programme was available,
and the conference was funded entirely by the REHE programme.
While the first REHE conference focused on relativistic pseudopotential
methods, and the second one on four-component methodology, the present
third one was mainly focused on applications of relativistic theory.
Nevertheless, relativistic theory was addressed in several lectures, in
particular in connection with specific problems in applications.
A most interesting issue was risen in the theory of the correlation of
relativistic electrons, which was presented by Jacek Karwowski (Torun)
and Werner Kutzelnigg (Bochum). Due to the complicated nature of the
singularities involved, the situation is not entirely clear, and it appears
that a consistent treatment of the two-electron cusp in the relativistic case
is still lacking. A second theoretical topic, which was repeatedly addressed
by several speakers, is the effective reduction of the number of degrees
of freedom by transforming the four-component equations to a lower number
of components (two components, or even one in a spin-averaged theory).
As Kenneth Dyall (Moffett Field) stressed, the effect of the components which
have been integrated out is not neglegted in these theories, since operators
resulting from the odd part of the four-component operators are explicitly
present in the reduced theories. Andrzej Sadlej (Lund) showed a generalization
of the Douglas-Kroll transformation, which is capable of reproducing the
Dirac equation values for one-electron atoms to any desired accuracy in
the fine-structure constant. Likewise, the Regular Relativistic Approximations
presented by Evert Jan Baerends (Amsterdam) are able to describe relativistic
effects to any desired order. Thus, the theory of two-component relativistic
Hamiltonians seems to be mature, and the long-standing problems with highly
singular operators resulting from the truncated Foldy-Wouthuysen transformation
are history by now.
These methods are particularly useful in the framework of pseudopotentials,
and the state of the art in this field was summarized by Christian Teichteil
(Toulouse). Walter Ermler (Argonne) contributed a new definition of a large-core
pseudopotential, and Paolo Palmieri (Bologna) described in detail the technical
aspects of the calculation of spin-orbit coupling matrix elements between
correlated wave functions. An interesting aspect of relativistic theory was
addressed by Jens Peder Dahl (Lyngby), who lectured on the relativistic Kepler
problem, in particular the supersymmetric properties of the Dirac equation.
The first session on applications dealt with relativistic effects on nuclear
magnetic resonance chemical shifts. The relativistic effects in NMR (which are
to a large extent spin-orbit effects) were treated in a quantum-chemical
framework by Hiroshi Nakatsuji (Kyoto) and by means of density functional
theory by Vladimir Malkin (Bratislava). Without doubt, both methods will be
developped further, the introduction of four-component methods and the
treatment of electron correlation in a quantum-mechanical framework as reported
by Lucas Visscher (Odense) being the most important issues.
One of the most stunnning features in the applications of spin-orbit coupling
theory, was the importance of relativistic effects in the chemistry of
comparatively light elements. Even the reaction of F + H_2 as studied by
Hans Joachim Werner (Stuttgart) is to a large extent influenced by
spin-orbit effects. David Yarkony (Baltimore) contributed examples in heavier
systems. Similar issues were discussed by Boris Minaev (Cherkassy) under the
aspect of spin catalysis. The coupling of various spin angular momenta
in the theoretical spectroscopy of transition metal compounds was discussed
by Christel Marian (Bonn) and compared to experimental results.
Obviously, experiments on relativistic systems present an important challenge
for the theoretical work. So the lectures by Arne Haaland (Oslo) on the
gas-phase structure of molecular compounds of the 5th and 6th row of the
periodic table, studied mostly by gas electron diffraction, and the lecture
by Lester Andrews (Charlottesville) on matrix-isolation spectroscopy of
heavy molecular systems were received very favourably.
Peter Schwerdtfeger (Auckland) reviewed recent quantum-chemical calculations
on compounds of superheavy elements, which are characterized by the most
advanced treatment of electron correlation. Pekka Pyykko (Helsinki) presented
a discussion of spin-orbit coupling in chemical bonding, and the turned on
on the calculation of quadrupole coupling constants, stressing that the
combination of theoretical 'q' and experimental 'e^2 qQ/h' provides
international standards for this quantity.
The last day featured applications of relativistic theory in the solid state,
providing most advanced topics with important impact in the research on new
materials. Zoila Barandiaran (Madrid) uses embedded-cluster methods with
a spin-free transformed Hamiltonian to define models for crystalline materials,
in particular such with transition metal atoms. Hubert Ebert (Munich)
lectured about the theoretical treatment of magneto-optical effects in solids
using density functional theory, addressing topics important for industrial
applications as anisotropic magnetoresistance and the magneto-optical Kerr
effect. Finally, a recent relativistic theory of superconductivity was
presented by Balasz Gyorffy (Bristol).
It can be concluded that chemical applications of relativistic theory are
manifold. Chemical notions like the 'heavy atom effect' in NMR and spin
recoupling phenomena in chemical reactions find their common theoretical
framework in relativistic quantum chemistry. Spin-orbit coupling is a
relativistic effect well known from atomic and molecular spectroscopy, and
theoretical treatment of these effects is now routinely possible.
Applications on magnetic materials and materials featuring transition metals
require relativistic theory for proper prediction and description of
properties. It was generally felt that the applications of relativistic
electronic structure theory of molecules are still at their beginning, and
that monitoring the progress in a fourth research conference in about two
years is highly desirable.
Bernd Hess
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
================================================================================
--- P A P E R S F U N D E D B Y R E H E
>>> please send a preprint of papers funded by REHE to Bernd A. He\ss,
>>> Institut f\"ur Physikalische und Theoretische Chemie, Universit\"at Bonn,
>>> 53115 Bonn, Germany
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[communicated by Klaus Capelle]
K. Capelle and E.K.U. Gross
"Spin-density functionals from current-density functional theory
and vice versa: A road towards new approximations"
Phys. Rev. Lett. 78, p.1872 (1997)
K. Capelle, E.K.U. Gross and B.L. Gyorffy
"Theory of Dichroism in the Electromagnetic Response of
Superconductors"
Accepted for publication in Phys. Rev. Lett. 1997
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
--- P O S I T I O N S available
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[no material for this section in the current newsletter]
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
================================================================================
--- P O S I T I O N S sought
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[no material for this section in the current newsletter]
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
================================================================================
--- ADDRESS LIST
The REHE address list comprises 193 scientists as of April 28, 1997; the
next address list will be provided with newsletter no. 25
This newsletter is mailed to all collegues presently in the REHE mailing
list.
In order to join the REHE mailing list, please complete the form below
and send it back per e-mail to hess@uni-bonn.de
>>> PLEASE include TEL, FAX, E-MAIL <<<
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End of REHE Newsletter No. 24