PROJECTS

Coupling of density-functional and configuration-interaction-type methods

PRINCIPAL INVESTIGATOR

Prof. Dr. Hermann Stoll Universität Stuttgart Theoretische Chemie Pfaffenwaldring 55 70569 Stuttgart (+49)711/685-4410 (+49)711/685-4442 stoll@theochem.uni-stuttgart.de

TOGETHER WITH

Prof. Dr. Hans-Joachim Werner Universität Stuttgart Theoretische Chemie Pfaffenwaldring 55 70569 Stuttgart (+49)711/685-4401 (+49)711/685-4442 werner@theochem.uni-stuttgart.de

ABSTRACT

Various approaches of coupling density-functional (DFT) with configuration-interaction (CI) type methods will be tested. The main emphasis is on separating the interelectronic interaction into a short-range part which is treated by DFT and a long-range part which is treated by multi-configuration self-consistent-field (MCSCF) and multi-reference CI methods. By changing the value of the coupling parameter, the CI admixture to DFT can be varied, i.e., the accuracy of DFT can be systematically improved. On the other hand, the computational effort of the CI part can be kept small due to the absence of the interelectronic cusp in the long-range wavefunction. Problems of describing potential-energy surfaces at the pure DFT limit (inability of describing bond-breaking, e.g.) will be tackled by means of a correction scheme combining open-shell DFT and MCSCF information.