On the Exact Evaluation of Intermolecular Electrostatic Interaction Energy in a Molecular Coordinate System

Abstract

We propose an effective general approach for accurately calculating the electron-electron, nuclear-electron and nuclear-nuclear Coulomb electrostatic interaction energies. Since these interaction energies are fundamental terms in the ab initio, density function and semi-empirical theories, their general examination will make an important contribution to the accurate calculation of the physical and chemical properties of atoms and molecules. It is well known that electron-electron, nuclear-electron and nuclear-nuclear Coulomb electrostatic interaction energies can be reduced to basic two-center Coulomb integrals. The analytical calculation of electrostatic interaction energies with respect to basic two-center Coulomb integrals over Slater type orbitals (STOs) in molecular coordinate systems allows for the routine evaluation of molecular structures and their related properties. In this study, we introduce a new full analytical algorithm for calculating the basic two-center Coulomb integrals over STOs using Guseinov’s auxiliary functions, especially the interactions between electrons. The auxiliary functions are calculated by using the exact recurrence relations developed by Guseinov. Our new approach is successfully tested on data from previously published studies, and can be recommended for the evaluation of related problems in atomic and molecular physics.