A semi-empirical theory of the electronic structure of ethylene with particular reference to the ionization potential

Abstract

The electronic structure of the ethylene molecule is rescrutinized within the framework of the semi-empirical pi-electron theory. The lower electronic energy levels, twisting frequency, ionization potential and electron affinity are calculated without treating the so-called β parameter as empirical. A new approach for calculating the ionization potential is presented, in which an allowance is made for the change in the effective nuclear charge accompanying the actual ionization. The ionization potential is computed to be 10·757 ev, the observed value being 10·62 ev.