Berlin 2005 – wissenschaftliches Programm
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A: Atomphysik
A 13: Poster HU 2
A 13.41: Poster
Dienstag, 8. März 2005, 08:30–18:30, Poster HU
Doubly excited autoionizing states of H2 converging to the H(n=2)+H(n’=2) limit — •Yulian Vanne und Alejandro Saenz — AG Moderne Optik, Institut für Physik, Humboldt-Universität zu Berlin, Hausvogteiplatz 5-7, D – 10117 Berlin, Germany
The renewed interest in diatomic molecules, especially alkali dimers, motivated us to implement a new state-of-the-art ab initio code that should allow the accurate treatment of (effective) two-electron diatomic molecules. The diatomic two-electron problem is solved using B splines that have already earlier been shown to provide a good tool for treating atoms as well as molecules. However, in contrast to previous work a prolate-spheroidal coordinate system is used that allows to fully explore the diatomic symmetry. The (effective) one-electron problem is solved first in order to provide a suitable basis for the subsequent (full) configuration interaction (CI) calculation. The doubly excited Q(2) states of H2, which are of interest for H(2s)+H(2s) collisions, have been calculated for short as well as for large internuclear distances. In the asymptotic region good agreement is found with the van-der-Waals behaviour given by C3, C5, and C6 coefficients. In fact, the quality of the ab initio results allowed to detect errors in previous calculations of these van-der-Waals coefficients.