On the Theory of the π-Electron System in Porphines

Abstract

The failure of certain LCAO molecular orbital calculations of the spectrum of porphine is attributed to the incorrect assumption of complete ``aromaticity.'' A division of the π‐electron system into non‐interacting parts is supported by the fact that the dynamical properties of the divided system, as calculated by the free‐electron model, are in approximate agreement with experiment. A proof of the equivalency of the LCAO method (with overlap neglected) and an approximation to the free‐electron method is indicated for certain dynamical systems.