Quantum-chemical study of the spectral properties of stilbene isomers

Calculations of absorption spectra of cis- and trans-forms of stilbene by the quantum-chemical method of intermediate neglect of differential overlap with spectroscopy parametrization were carried out. The electron structure of a stilbene molecule was studied and energy-level diagrams were drawn and analyzed. Rate constants of different photophysical processes occurring in a stilbene molecule after absorption of a photon were calculated in relation to the molecule conformation. On the basis of the obtained results, possible configurations of photoisomer molecules were considered and the most probable configurations of excited stilbene molecules were determined. It was shown how the change in the configurations of cis- and trans-forms of stilbene affects its spectral properties. (C) 2002 MAIK "Nauka/Interperiodica".