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Analysis in der Fachoberschule
(Bardy, P. (Hrsg.), 1988)
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Solution of the Hartree-Fock-Slater equations for diatomic molecules by the finite-element method
(1988)
We present the finite-element method in its application to solving quantum-mechanical problems for diatomic molecules. Results for Hartree-Fock calculations of H_2 and Hartree-Fock-Slater calculations for molecules like N_2 and CO are presented. The accuracy achieved with fewer than 5000 grid points for the total energies of these systems is 10^-8 a.u., which is about two orders of magnitude better than the accuracy of any other available method.
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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 ...
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Accurate Hartree-Fock-Slater calculations on small diatomic molecules with the finite-element method
(1988)
We report on the self-consistent field solution of the Hartree-Fock-Slater equations using the finite-element method for the three small diatomic molecules N_2, BH and CO as examples. The quality of the results is not only better by two orders of magnitude than the fully numerical finite difference method of Laaksonen et al. but the method also requires a smaller number of grid points.
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Molecular effects on the cross section for pair production and their importance in the evaluation of the total photonuclear cross section of {^16}O in the {\delta-resonance} region
(1988)
The screening correction to the coherent pair-production cross section on the oxygen molecule has been calculated using self-consistent relativistic wave functions for the one-center and two-center
Coulomb potentials. It is shown that the modification of the wave function due to molecular binding and the interference between contributions from the two atoms have both sizeable effects on the screening correction. The so-obtained coherent pair-production cross section which makes up the largest part of the total atomic ...
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Theme group 6: Mathematics and other subjects
(Hirst, Ann (Hrsg.), 1988)
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Theory for the Photoacoustic Response to X-Ray Absorption
(American Physical Society, 1988)
A microscopic theory is presented for the photoacoustic effect induced in solids by x-ray absorption. The photoacoustic effect results from the thermalization of the excited Auger electrons and photoelectrons. We explain the dependence of the photoacoustic signal S on photon energy and the proportionality to the x-ray absorption coefficient in agreement with recent experiments on Cu. Results are presented for the dependence of S on photon energy, sample thickness, and the electronic structure of the absorbing solid.
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Hyperfine structure and isotopic shift of the n^2 P_J levels (n = 7-10) of ^203,205 TI measured by Doppler-free two-photon spectroscopy
(1988)
Using Doppler-free two-photon absorption spectroscopy, we have measured hyperfine splitting constants as well as isotopic level shifts of the 6s^2 np ^2 P_l/2,3/2 states in (n=7-10) in ^203 TI and ^205 TI.
Calculations for hyperfine constants and electron density at the nucleus have been performed by the Dirac-Fock method. The experimental results are compared with these calculations as well as with
the predictions of the semiempirical theory.