*************************************************************** **** **** **** ESF Programme **** **** **** **** RELATIVISTIC EFFECTS IN HEAVY ELEMENT CHEMISTRY **** **** AND PHYSICS **** **** **** *************************************************************** Newsletter No. 9 (17 October 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). ================================================================================ --- E D I T O R I A L 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 (#10) is scheduled for Beginning of December 1994. Please send your contributions until end of November 1994. Please send material >by e/mail< that enables us to fill the following topics in forthcoming newsletters ================================================================================ --- E S F B A C K G R O U N D The European Science Foundation was established in 1974. Its Member Organizations are the major European academies, research councils and other institutions supporting scientific research nationally. Although these are funded mainly by governments, the ESF itself is a non-governmental organization. It maintains close associations with other international bodies with interests in scientific research, particularly the Commission of the European Communities and the Academia Europaea. How ESF works ESF pays for its activities through the contributions of its Member Organizations. Contributions are made both to the ESF basic budgets, to which member organizations contribute on a scale that is calculated on the basis of national incomes, and to specific programmes and projects in which certain Member Organizations may have particular interest. The modes of ESF scientific work vary with the expressed needs, and may change in character over the years. Broadly, ESF Scientific Programmes almost always contain teams of scientists who carry out research. ESF Scientific Networks discuss, plan, innovate, analyse or co-ordinate research, but seldom carry out large amounts of substantive research. Programmes are often long-term, and are funded (except in the development phase) by participating Member Organizations. Networks are usually of shorter term (three years); they are funded from the Network Account within the ESF basic budget. ESF also organizes, jointly with the Commission of the European Communities, a programme of European Research Conferences. ================================================================================ --- 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. >>> Should the planned dates of your stay change for any reason, you are >>> requested to notify the Chairman 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. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ [communicated by I. Martin] REPORT ON THE VISIT BY INMACULADA MARTIN TO PROFESSORS KARWOWSKI AND DIERCKSEN ON REHE GRANT No. 10. Place: Max-Planck-Institut fuer Astrophysik; Garching bei Muenchen, Germany Dates: 1-31 August 1994 Subject: A universal pattern of the QDO oscillator strengths in atoms. Atomic oscillator strengths calculated with the quantum defect orbital (QDO) method depend upon a certain combination of the quantum numbers, degree of ionization of the atom, and the energies of the two states involved. However, the f-values are independent of the number of electrons and the nuclear charge. If the degree of ionization and the quantum numbers are fixed, then the QDO oscillator strength is just a function of the state energies and is independent of the specific atom. As a result of this study, the QDO f-values have been expressed as universal functions of the state energies in both relativistic and non- relativistic formulations of the theory. The results, in addition to their practical usefulness (they allow for an immediate estimation of oscillator strengths) permit a deeper understanding of the relations between direct and indirect relativistic effects in the QDO approach. ---------------------------------------------------------------------- OUR MOST RECENT PUBLICATIONS ON RELATIVISTIC CALCULATIONS -"Relativistic quantum defect calculations on the Cu isoelectronic sequence" C. Lavin, C. Barrientos, I. Martin International Journal of Quantum Chemistry 50 (1994), 411. -"Core polarization effects in the relativistic quantum defect orbital theory" D. Bielinska-Waz, I. Martin, J. Karwowski Acta Physica Polonica 85 (1994), 805. -"Triplet-triplet transitions in zinc-like ions" P. Martin, C. Lavin, I. Martin Z Physik D: Atoms, Molecules and Clusters 30 (1994), 279. -"Relativistic quantum defect orbital calculations on triplet-triplet transitions in cadmium-like ions" C. Lavin, I. Martin Journal of Quantitative Spectroscopy and Radiative Transfer 52 (1994), 21. -"Measurements and calculations of the oscillator strength spectral density of Cd" M. Amad, U. Griessman, I. Martin, A.M. Baig Journal of Physics B: Atomic, Molecular and Optical Physics, to appear (1994). ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ [communicated by P. Marketos] Dr. Fumihiro Koike, of School of Medicine, Kitasato University, Japan, visited the Foundation for Reasearch and Technology (FORTH) offices in Athens, and discussed with Dr Pan Marketos large scale MCDF-CI calculations for 2p ---> 3d excitations in elements of the first transition series. Professor Ian Grant is also involved in the theoretical part of this project. Calculations are performed using the GRASP code. Experimental groups in Japan are also involved. Results for Mn are satisfactory. For this atom, the spectrum in the 2p-absorption region measured by photoion yield method agrees quite well with the convoluted curve in which a Lorentzian natural profile and a triangular apparatus function are applied for each oscillator strength. In another project involving GRASP, the structure of high lying levels of the type 2p^5 4f in NaII, 2p^4 5g in NaIII and 2p^3 6h in NaIV has been investigated. Beam-foil spectroscopic studies as well as excitation function studies on these ions have been carried out at the Tata Institute of Fundamental Research, Bombay. Experimentally determined lifetimes for these levels agree quite well with theoretical calculations performed in collaboration with Dr Pan Marketos (FORTH, Athens). As a result, tentative assignments for the levels involved in experimentally determined transitions have also been provided. The calculation showed that the nf, ng and nh orbitals used for the description of the ionic levels may be treated as hydrogen-like. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ [communicated by M. Barysz] Report on results obtained by Maria Barysz during a three-month fellowship granted within the REHE project. Author: Maria Barysz Host: Geerd H. F. Diercksen Place: Max-Planck-Institut fur Astrophysik, Garching bei Munchen Time: 20.06.94 - 20.09.94 Subject: Developing methods for simultaneous inclusion of electron correlation and relativistic effects in theory of molecular structure. DESCRIPTION OF THE PROJECT AND RESULTS Motivation. Importance of relativistic effects in describing properties of atoms and molecules has been recognized long ago. Some phenomena, as for example spin-forbidden electronic transitions or fine-structure splittings, cannot be described at all without taking into account relativistic effects. Many other properties are considerably dependent on the relativistic effects. Relativistic effects appear to be important also in systems containing light elements only. Particularly in these cases the theoretical description may be very accurate on the non-relativistic level and therefore including relativistic effects becomes an imperative if a good agreement with experiment is to be expected. During last several years a general multi-reference non-relativistic direct CI programme based on the symmetric group approach (SGA) to theory of many-electron systems has been developed in Garching. It allows for accurate, non-relativistic, treatment of small molecules. Therefore, at this stage of development of the code, the low-order relativistic effects have to be included. Method. SGA has also been applied to construct CI algorithms in the case of spin dependent Hamiltonians. However, then the degree of complication of the method is much higher. Instead of the representation matrices of the permutation group which are easy to obtain from many algorithms, matrices that depend upon the form of the spin-dependent part of the Hamiltonian appear in the matrix element expressions. The formalism, in its general form, has been developed and detailed formulae have recently been derived. As a result, general expressions for matrix elements of spin-dependent operators in a basis of non-relativistic configurations have been obtained. This allowed for a formulation and coding of a configuration interaction method based on the Pauli approximation. This kind of approach proved to be very successfull in the case of atoms. It is anticipated that also in the case of molecules containing atoms with low and medium nuclear charges the method should be applicable. It is much simpler than the ones based on the full (four-component) relativistic treatment. The CI method using an explicit projection onto the positive-energy subspace (the no-pair approach) is being implemented now. It will further extend applicability of the method. An immediate goal of this project is to implement a spin-dependent CI method in both standard Pauli and in the no-pair modes. Scientific goals. Studies on the electric and magnetic properties of molecules in the spin dependent formalism, studies on spin-forbidden transitions, investigation of the influence of the spin-orbit coupling on structure of the energy hypersurfaces, just to mention the most important directions of the studies. The main objective of the present project is to extend the nonrelativistic symmetric-group-approach-based CI (SGA-CI) programme to include relativistic effects within scalar approximations. The nonrelativistic SGA CI code has been developed in Garching as a result of cooperation between G. H. F. Diercksen, W. Duch, and J. Karwowski [1]. The one-electron Breit-Pauli relativistic corrections have been very recently added to this code by N. Flocke and M. Barysz in cooperation with G. H. F. Diercksen and J. Karwowski. During the last three months Maria Barysz has been working on two problems: I. Calculation of the two-electron Breit-Pauli relativistic corrections. The following two-electron corrections have been programmed: Two-electron spin-other-orbit interaction. Two-electron spin-spin interaction and Fermi contact interaction Two-electron orbit-orbit interaction. Two-electron Darwin correction. All integrals appearing in these corrections have been expressed as combinations of the overlap integrals and the electron-repulsion integrals. In effect, rather complicated expressions for the relativistic corrections may be handled in a simple way using subroutines for calculating the ``elementary'' integrals. These subroutines have been developed and optimized earlier in order to handle the nonrelativistic case. During the past three months all algorithms have been derived and most of them have been programmed. However, the relativistic CI code is rather far away from the stage in which it might be used in routine calculations. Now, testing correctness the code is the main problem. II. It has been recognized that including the no-pair approach [2], i.e. projection of the Hamiltonian onto the positive-energy subspace, essentially extends applicability of the programme. Therefore works aimed at an implementation of this approach within the SGA formalism have been undertaken. The algorithm for the algebraic approximation to the no-pair approach have been worked-out and, in a major part, implemented. However, similarly as in the case of the Breit-Pauli approximation, testing correctness of the code has not been performed yet. Several testing algorithms are being currently developed. References: [1] W. Duch and J. Karwowski, Comuter Phys. Rep. 2(1985)93; Theoret. Chim. Acta 71(1987)187; G. H. F. Diercksen, W. Duch and J. Karwowski, Phys. Rev. A41(1990)3503. [2] J. Sucher, Phys. Rev. A22(1980)348; J. Alml\"of, K. Faegri and H. H. Grelland, Chem. Phys. Letters 114(1985)53; B. A. Hess, R. J. Buenker and P. Chandra, Int. J. Quantum Chem. 29(1986)737; R. Samzow, B. A. Hess and G. Jansen, J. Chem. Phys. 96(1992)1227. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ [communicated by Stefan Keller] Status report of the relativistic (e,2e) project pursued by the Cambridge/Frankfurt/Belfast collaboration As was indicated in an earlier REHE newsletter, groups from Cambrigde (Whelan, Ast), Belfast (Walters) and Frankfurt (Keller, Dreizler) have been engaged in setting up a relativistic DWBA code to describe electron impact ionization of the innermost electrons of heavy metallic target atoms by a consistent first order calculation within Furry picture QED. While earlier theories have shown a pronounced tendency towards overestimating the absolute experimental results of Nakel and collaborators (Tuebingen), first results using our approach agree quite well with the experiment (PR A50, R1, PR A 50, in press). During visits of Stefan Keller to Cambridge and Belfast earlier this year, funded by the ESF through the REHE program, we have therefore started a comprehensive study of different target systems and kinematical conditions which is still under way due to the large amounts of CPU time needed. Furthermore, we have investigated the reasons for the failure of previous approximate first order theories. Over the summer, we have extended our work to include a spin polarized incident channel. Here a first experiment has been carried out by the Tuebingen group, but a number of conceptual prob- lems involving the definition of spin polarized relativistic electronic states in the presence of external fields has to be addressed in order to arrive at a sensitive theoretical description of the data. We expect that by systematically extending our method while maintaining a close collaboration with the experimentalists, the understanding of the basic ioniza- tion process of inner shells of heavy atoms will be further improved. S. Keller would like to thank the ESF for the continuous support of his work on this project. He also gratefully acknowledges the hospitality of the Cambridge and Belfast groups. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ [communicated by J. Sienkiewicz] Report on the ESF scholarship of J. E. Sienkiewicz at University of Oxford Within the REHE fellowship program, I spent three months (9 July - 8 October 1994) with Prof. I. P. Grant in the Mathematical Institute at University of Oxford. We collaborated on the relativistic multi-configurational method in the elastic low-energy scattering of electrons from atoms. During my stay in Oxford, I calculated the 'final' (including continuum orbital) and 'initial' (bound) multi-configuration states of the electron-xenon system. The 'initial' state accounts for correlation effects between the scattered electron and bound electrons from the target atom. First, I used the computer code GRASP2, developed in Oxford, to generate the relativistic ns, np and nd orbitals up to n = 12. Next, I made a CI calculation of the ground state of Xe and used these atomic orbitals for the CI calculation of the negative ion of Xe. I made an attempt to incorporate SCF orbitals of the negative ion in my scattering state, but it required too much time and after discussion with Prof. Grant I decided to work on it after my return to Gda\'nsk. I also developed further my own computer code by including new subroutines governing the SCF iteration process, calculating the relativistic phase shifts and solving the system of linear equations needed to calculate an eigenvector of the scattering multi-configurational state. Finally, using the RATR code of S. Fritzsche I obtained a converged solution of the continuum Dirac spinor. At the end of my stay, I wrote a theoretical chapter for an article which we shall publish. I am very grateful to ESF for providing funds for this project and I thank Prof. Ian P. Grant for the help and discussions during my stay in Oxford. I also thank Dr. Stephan Fritzsche for the assistance in customizing his computer code. J\'ozef E. Sienkiewicz ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ================================================================================ --- 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 H. Schmidbaur] Preliminary Announcement For 1995 Professor Notger Roesch and myself are planning to have a Symposium on Experimental and Theoretical Chemistry of Gold. Such a meeting will of course be of great interest to many colleagues engaged in research in the broad area of relativistic effects in the chemistry and physics of the heavy elements in general, and of gold in particular. The meeting will be held in the Munich area, readily accessible by air, rail, and road. It appears that September 1994 should be considered as a suitable period, and in a brief discussion with Professor Pyykkoe the days from September 8-13 were found to be most likely the best choice. We are thinking of a three-to-four day event, with experimentalists and theoretical groups well balanced in the program. A one-day week-end break should give a chance for recreation and personal contacts. As judged from the published research activities, a group of at least 60-80 people can be expected to participate from all over the world. We hope to be able to attract outside funding, but we will also have to rely on standard registration fees. I put this preliminary announcement into the REHE newsletter in the hope that all its readers are giving this proposal some thought and perhaps let me know if they are considering to participate. A more detailed leaflet will be available by December 1994. Thank you for your interest: Hubert Schmidbaur, TU Muenchen. ================================================================================ --- P O S I T I O N S available ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ OXFORD UNIVERSITY MATHEMATICAL INSTITUTE Postdoctoral Research Assistant in Mathematical Physics An EPSRC-funded Postdoctoral Research Assistantship is available to work on the relativistic R-matrix method for studying electron scattering from atoms and ions and photo-excitation/ionisation processes in heavy elements. The project will involve some theory as well as extension and optimization of existing code to run on supercomputers. Appointment will be on the academic-related research staff Scale 1A (salary \pounds 13,941 -- \pounds 18,486 per annum for a period of up to two years starting 1 January 1995, or as soon as possible afterwards. Applications are invited from those with an interest in applying relativistic quantum theory to atomic and molecular physics, or related fields, and having suitable computational experience. Applicants should send a curriculum vitae, including the names of two referees, to Professor I.\ P.\ Grant FRS, Mathematical Institute, 24-29 St.\ Giles', Oxford, OX1 3LB (Tel: +44 (0)865 273538/273551, Fax: +44 (0)865 273583, email: ipg@maths.ox.ac.uk) from whom further information can be obtained. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ================================================================================ --- P O S I T I O N S sought ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ [no material for this section in the current newsletter] ================================================================================ --- G O S S I P ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ [no material for this section in the current newsletter] ================================================================================ --- ADDRESS LIST The REHE address list comprises 127 scientists as of October 17, 1994; the current 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 <<< ================================================================= I am interested in receiving the REHE newsletter NAME ----------------------------------------------------------------- ADDRESS ----------------------------------------------------------------- ----------------------------------------------------------------- TEL ----------------------------------------------------------------- FAX ----------------------------------------------------------------- E-MAIL ----------------------------------------------------------------- MAIN RESEARCH INTERESTS ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ End of REHE Newsletter No. 9