AN APPROXIMATE METHOD OF COMPUTING ELECTRONIC CHARACTERISTICS OF LARGE MOLECULAR-SYSTEMS IN THE GROUND ELECTRONIC STATE

A semiempirical variant of the fragment method given in the preceding paper for quantum chemical calculation of large molecular electronic structures is proposed. The method is based on the CNDO approximation for fragment wave functions. Numerical calculations of the ground state energy and Mulliken atomic charges of polyatomic molecules such as biphenyl, 4-(phenyl)pyridine,4-fluorophenyl, triphenyl and quaterphenyl are given. The results are compared with direct calculations of these molecules by the CNDO/S method and are in rather good agreement, but computational time has proved to be considerably less in our method for large molecules than in the direct computational procedure.