Nonradiative relaxation of 2-phenylindene in solution and its implications for isomerization of stilbenes

The solvent dependence of the excited state photophysics of 2-phenylindene (PI) is explored here. The results show that the nonradiative process is activated with a barrier in excess of 6.8 kcal/mol. This finding is consistent with recent observations on PI in a supersonic jet. The implications of these findings for stilbene isomerization are discussed.