ESCA spectra and molecular charge distributions for some pyrimidine and purine bases

Abstract

A series of pyrimidine and purine bases bas been studied experimentally by electron spectroscopy for chemical analysis. Individual component peaks in the spectra were assigned on the basis of known substituent effects on core electron binding energies. Binding energies for all the core levels in the molecules provide sufficient data to determine the molecular charge distributions. The results compare favourably with atomic charges determined theoretically in the CNDO/2 molecular orbital formalism.