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Now showing items 41-50 of 75
Aufsatz
Theoretical evidence for quasi-molecular structure at small internuclear distances in elastic ion-atom scattering
(1985)
The potential energy curve of the system Ne-Ne is calculated for small internuclear distances from 0.005 to 3.0 au using a newly developed relativistic molecular Dirac-Fock-Slater code. A significant structure in the potential energy curve is found which leads to a nearly complete agreement with experimental differential elastic scattering cross sections. This demonstrates the presence of quasi-molecular effects in elastic ion-atom collisions at keV energies.
Aufsatz
Influence of the electronic shell structure on the elastic scattering of heavy ions
(1982)
The interatomic potential of the system I - I at intermediate and small distances is calculated from atomic DFS electron densities within a statistical model. Structures in the potential, due to the electronic shells, are investigated. Calculations of the elastic differential scattering cross section for small angles and several keV impact energies show a detailed peak pattern which can be correlated to individual electronic shell interaction.
Aufsatz
Interatomic potential structures in highly ionized scattering systems
(1983)
The interatomic potential of the ion-atom scattering system I^N+-I at small intermediate internuclear distances is calculated for different charge states N from atomic Dirac-Focker-Slater (DFS) electron densities within a statistical model. The behaviour of the potential structures, due to ionized electronic shells, is studied by calculations of classical elastic differential scattering cross-sections.
Aufsatz
Computation of relativistic symmetry orbitals for finite double point groups
(1989)
A program is presented for the construction of relativistic symmetry-adapted molecular basis functions. It is applicable to 36 finite double point groups. The algorithm, based on the projection operator method, automatically generates linearly independent basis sets. Time reversal invariance is included in the program, leading to additional selection rules in the non-relativistic limit.
Aufsatz
Shifts of electronic KX-rays in muonic atoms
(1982)
Energies of electronic K X-rays in muonic atoms were calculated for muons in various outer orbitals and for different numbers of electrons. Energy shifts were obtained with respect to characteristic X-rays belonging to nuclear charge (Z - 1) and their possible observation is discussed. The shifts in muonic Sn as an example amount to 19, 37, and 59 eV for the muon in 5g, 6h, and 7i states respectively. However, shifts due to the number of electrons present and the electron vacancy distribution in the L-shell are ...
Aufsatz
An attempt on the calculation of relativistic potential energy curves: noble gas difluorides
(1980)
Total energy SCF calculations were performed for noble gas difluorides in a relativistic
procedure and compared with analogous non-relativistic calculations. The discrete
variational method with numerical basis functions was used. Rather smooth potential
energy curves could be obtained. The theoretical Kr - F and Xe - F bond distances were calculated to be 3.5 a.u. and 3.6 a.u. which should be compared with the experimental values of 3.54 a.u. and 3.7 a.u. Although the dissociation energies are off by a factor of ...
Aufsatz
On the total energy of two-electron atoms
(1985)
Using the Multi-Configuration Dirac-Fock (MCDF) method we calculate with 9 configuration state functions the correlation energy as well as the total energy of the lowest J = 0 ground state of all two-electron systems from H- to Thorium (Z = 90). A comparison with experimental data, which are available only in the low Z region, shows a very good agreement.
Aufsatz
Relativistic many-electron SCF correlation diagram for superheavy quasimolecules: Pb - Pb
(1981)
We present the first relativistic many-electron SCF correlation diagram for a superheavy quasimolecule: Pb - Pb. The discussion shows a large number of quantitative as well as qualitative differences as compared with the known one-electron correlation diagram.
Aufsatz
Kr - Kr correlation diagram and its use in heavy-ion collisions
(1981)
A realistic self-consistent charge correlation diagram calculation of the Kr{^2+} - Kr{^2+} system has been performed. We get excellent agreement for the 4(3/2)_u level with an experimentally observed MO level at large distances. Possible reasons for discrepancies
between experiment and theory at small distances are discussed.
Aufsatz
{2p_\pi}-{2p_\sigma} crossing in heavy symmetric ion-atom collisions: I. Level structure
(1982)
Ab initio self-consistent DFS calculations are performed for five different symmetric
atomic systems from Ar-Ar to Pb-Pb. The level structure for the {2p_\pi}-{2p_\sigma} crossing as function of the united atomic charge Z_u is studied and interpreted. Manybody effects, spin-orbit splitting, direct relativistic effects as well as indirect relativistic effects are differently important for different Z_u. For the I-I system a comparison with other calculations is given.