Ground States of σ-Bonded Molecules. IX.1: The MINDO/2 Metho

Abstract

A computer program has been written for automatically optimizing the parameters in MO treatments. Using this, and using parametric functions for the core resonance integrals and core–core repulsions similar to those used in the PNDO approximation, we have been able to develop a version (MINDO/2) of the MINDO method which gives good estimates of bond lengths, heats of formation, and force constants simultaneously for a wide variety of hydrocarbons, thus satisfying the minimum requirements for a procedure to be used convincingly for calculating potential surfaces. Potential surfaces are calculated for the torsional isomerization of ethylene and cumulenes, for hydrogen abstraction reactions of methyl, and for the dimerization of ethylene. The results are encouraging. The method also gives good estimates of first ionization potentials. © 1970, American Chemical Society. All rights reserved.