AVERAGE ENERGIES OF COMBINING STATES AND THE 0-0-TRANSITION FREQUENCY OF ELECTRON-VIBRATIONAL SPECTRA

Abstract

It is shown that the Frank-Condon principle, the thermal equilibrium population of sublevels of the initial electronic state, and the independence of the probability of elementary transitions of the temperature permit to find the frequency of the electronic 0-0-transition (n₀₀) not only from the dependence of the cross-section spectra s(n) on frequency, but also from their relative changes with the variation of the temperature. In this case, n₀₀ corresponds to the minimum of the dependence of the sum of the average energies of combining states on the frequency or to the extremum of the function ±hn/2 - ¶ln(s(n))/¶(1/kT) (the signs“+” and “-“ should be used for the absorption and emission, respectively) on the same parameter. The approach is tested on vapor spectra of some substances and show better precision than that by frequency dependence, especially for overlapped spectra.