Electronic structure of diazocyclopentadiene. A study using low and high energy photoelectron spectroscopy and ab initio molecular orbital calculations

Abstract

The He I, He II and X-ray photoelectron spectra of diazocyclopentadiene are reported and interpreted using ab initio SCF MO calculations. The low energy spectra are satisfactorily discussed in terms of Koopmans' theorem, but the use of this approximation to discuss the nitrogen 1s spectrum leads to an incorrect conclusion with regard to the charge distribution in diazocyclopentadiene because of the greater orbital relaxation accompanying core ionization from this molecule than from molecular nitrogen.