Molecular Orbital Theory of the Electronic Structure of Organic Compounds. IV. Internal Rotation in Hydrocarbons Using a Minimal Slater-Type Basis

Abstract

Self-consistent molecular orbital theory with a minimal basis of atomic orbitals is used to study internal rotation in hydrocarbons with two, three, or four carbon atoms. For the range of conformations in which steric interactions are not strong, calculated energy differences are found to be insensitive to the choice of bond lengths and bond angles. However, if steric interactions are large, the rigid rotor model is found to be inadequate. Good results are then obtained with a flexible rotor model in which each CCC angle is separately optimized for each conformation considered. © 1970, American Chemical Society. All rights reserved.