Electronic absorption spectra of 2,3- and 2.5-dimethylpyrazines

Abstract The electronic absorption spectra of 2,3- and 2,5-dimethylpyrazines were recorded and analysed considering C 2ν and C 2h symmetry for the molecules, respectively. Vibrational analysis of the electronic spectra of these molecules has shown the existence of a vibronic interaction between two electronic states of both the molecules through an out-of-plane bending mode.