Use of the CNDO Method in Spectroscopy. IV. Small Molecules: Spectra and Ground-State Properties

Abstract

The modified CNDO method has been applied to the study of the electronic-absroption spectra of several small molecules; namely, formaldehyde, formic acid, formamide, allene, ketene, and diazomethane, with quite satisfactory results. The lowest energy excited state of the last three compounds has been assigned as the state which arises from a π → π′* transition. A study has also been made of the calculation of ground-state properties from the spectroscopic parameterization. It has been concluded that although this method can give reasonable estimates of these properties, it is most reliable when used to evaluate ground-state properties which depend upon calculated eigenvalues.