Search

The correlation contribution to the static–exchange interaction potential (ΔVSE) appears as an important quantity in the electron molecule scattering calculations. We have shown that the single and double excitation configuration interaction (CISD) method does not give reliable results for ΔVSE. Only properly chosen multireference CISD calculation or Green’s function based calculations were found to be reliable. In this paper we carry out the coupled cluster (CC) calculations to test whether good results are obtained or not. The CC method will also help us to identify the important contributions to ΔVSE and to understand why a low order CI performs poorly. [ABSTRACT FROM AUTHOR]