Theory of electronic spectra of organic molecules

Abstract

A theory of the electronic spectra of organic molecules is outlined. The wave-mechanical resonance characteristic for the excited states of polyelectronic systems involves a fluctuation of the transition energy and, in this sense, represents a physical phenomenon which is absent in ground states. An analysis of the electronic perturbations resulting from resonance offers a qualitative, but very detailed, understanding of the observations and conclusions summarised in the author's classification of electronic spectra, if molecular structures are considered to be built up of localised bonds only. The electronic transitions responsible for R-, K-, and the effect of terminal groups and of substituents of absorbing systems on the positions of these bands are interpreted.