Accession Number : AD0612588

Title :   A SEMI-EMPIRICAL MO THEORY OF SIGMA ELECTRON SYSTEMS. I. GENERAL THEORY,

Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA

Personal Author(s) : Hamano,Hidekazu

Report Date : 10 MAR 1964

Pagination or Media Count : 10

Abstract : A semi-empirical Molecular Orbital (MO) theory is proposed for complex saturated molecules. In a firstorder treatment, each MO is represented as a localized function that contains only the Atomic Orbital connected with one bond or atom. This enables us to define a set of bonding, anti-bonding and lone-pair orbitals. The molecular wave function is obtained as an anti-symmetrized product of the bonding and lone-pair orbitals. In this approximate theory the definitions of the electronegativity scale and of the inductive effect are discussed; the electronegativity scales proposed by Moffitt and Mulliken are obtained as special cases. In a subsequent, more accurate second-order theory each MO is represented as a linear combination of all bonding, anti-bonding and lone-pair orbitals; this treatment is made by means of the perturbation theory. A semi-empirical approach is developed by taking the interactions between different bonds as empirical parameters. (Author)

Descriptors :   (*CHEMICAL BONDS, FIELD THEORY), (*MOLECULAR STRUCTURE, FIELD THEORY), ATOMIC ORBITALS, ELECTRONS, ATOMIC ENERGY LEVELS, PERTURBATION THEORY, RESONANCE, COMPLEX COMPOUNDS

Distribution Statement : APPROVED FOR PUBLIC RELEASE