Low temperature vibrational and vibronic spectra of adenine single crystals

Abstract

Both polarized UV absorption and Raman spectra of adeninium sulphate single crystals were measured at 10 K on the same modular UV-VIS spectrometer. Sharp vibronic structure of the lowest-energy absorption band of N1,N7 diprotonated adenine is interpreted in terms of Herzberg-Teller theory. Slight change of adenine molecule geometry localized round the amino group, which is caused by the electronic excitation, and strong vibronic coupling of some vibrational modes with other electronic transitions have been found.