Interatomare Austauschenergien und Potentiale zwei- und dreiatomiger Systeme

Abstract

In this thesis the interactions in two and three atomic molecules are investigated. The interaction energies can mainly be traced back to atomic parameters. Because of this fact, atomic wave functions are discussed in the beginning of the thesis. In the foreground of the interest are the asymptotic behavior and the normalization constants occuring in this occasion. For alkali atoms, the normalization constants can be determined exactly with pseudo-potential methods. For atoms and ions with two electrons, a model wave function is developed which has the correct asymptotic behavior, the correct behavior for small electron-electron distances and for small electron-nucleus distances. The percentage of the correlation energies calculated with this parameter-free wave function are in between 95% for H"- and 85% for Ne"8"+. In order to determine the normalization constants of helium as well as of the other rare gas atoms, configuration interaction calculations are performed. The exchange energy of two atomic van der Waals molecules is written as the product of the exchange energy of single electron pair and a angular momentum factor. Parallel to this, the same factor is determined with a simple counting rule. The exchange energies of the single electorn pairs are calculated by the surface integral method. The Generalized Heitler-London theory of Tang and Toennies is extended to many-electron systems and applied to He_2, Ne_2 and Ar_2282 refs.Available from TIB Hannover: RA 1396(1996,6) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman