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 $\mathrm{\pi \hspace{0.17em}\to \hspace{0.17em}\pi \prime *}$ 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.