Average dipole polarizabilities from the unsold approximation and ab initio data

Abstract

An approximate static dipole polarizability equation is developed on the basis of the Unsold approximation, and is cast in closed shell LCAO MO SCF formalism. A brief study is made of the use of Koopmans' theorem as a means of obtaining an average ionization energy, necessary in the polarizability equation presented. Average polarizabilities for the systems He, Ne, H 2, HF, H 2O, NH 2, CH 4, HCN, N 2, C 2H 2, C 2H 4, C 2H 6, C 6H 6, and C 6H 5F are calculated from the dipole polarizability expression developed using a small 4-31G basis set level. Results show good agreement with experimental data.