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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.
Aufsatz
Many-electron relativistic calculation and interpretation of atomic processes in time dependent heavy-ion scattering
(1989)
The time dependence of a heavy-ion-atom collision system is solved via a set of coupled channel equations using energy eigenvalues and matrix elements from a self-consistent field relativistic molecular many-electron Dirac-Fock-Slater calculation. Within this independent particle model we give a full many-particle interpretation by performing a small number of single-particle calculations.
First results for the P(b) curves for the Ne K-hole excitation for the systems F{^8+} - Ne and F{^6+} - Ne as examples are discussed.
Aufsatz
State-dependent volume isotope shifts of low-lying states of group-IIa and -IIb elements
(1985)
Results of relativistic multiconfiguration Dirac-Fock calculations with an extended nucleus are used to analyze the volume isotope shifts of the resonance transitions in the group-IIa and -IIb elements
as well as in Yb. This is done together with a review of the isotope shift theory, including a critical evaluation and comparison of the semiempirical calculation of volume isotope shifts commonly
used today. Electronic factors F_i, proportional to differences of electronic densities over the nuclear volume, are ...
Aufsatz
Analysis of the electronic structure, hyperfine structure, and volume isotope shifts in the low lying states of BA I and BA II
(1988)
Relativistic multi-configuration Dirac Fock (MCDF) wavefunctions coupled to good angular momentum J have been calculated for low lying
states of Ba I and Ba II. These wavefunctions are compared with semiempirical
ones derived from experimental atomic energy levels. It is found that significantly better agreement is obtained when close configurations are included in the MCDF wavefunctions. Calculations of the electronic part of the field isotope shift lead to very good agreement with electronic factors
derived from ...
Aufsatz
Test for basis-set errors in relativistic Dirac-Fock-Slater calculations with a numerical AO-DFS-basis
(1987)
A fully relativistic four-component Dirac-Fock-Slater program for diatomics,
with numerically given AO's as basis functions is presented. We discuss the problem of the errors due to the finite basis-set, and due to the influence of the negative energy solutions of the Dirac Hamiltonian. The negative continuum contributions are found to be very small.
Aufsatz
Spin-polarized Hartree-Fock-Slater calculations in atoms and diatomic molecules with the finite element method
(1990)
We present spin-polarized Hartree-Fock-Slater calculations performed with the highly accurate numerical finite element method for the atoms N and 0 and the diatomic radical OH as examples.