The local approach: Electronic correlations in small hydrocarbon molecules

Abstract
The local approach for the computation of electronic correlation energies is applied to ab initio calculations for C2H2, C2H4, and C2H6. Specific correlation patterns arise from the different kinds of bonds. They are investigated and explained. The accuracy of the local approach is improved so that experimental energies can be predicted with high precision. Finally we discuss the range of applicability of this calculational scheme.