Studies on radical ions in the excited states using pulse radiolysis and flash photolysis combined method

Stilbene radical cations (St.+) in the excited state have been studied with respect to their lifetimes and transient phenomena using pulse radiolysis-flash photolysis combined method. In the deactivation of the D2 state of cis-St.+, the internal conversion competes with the isomerization to trans-St.+ in a quantum yield of 0.49, whereas the D2 states of t-St.+ and 1,2-diphenylcyclo-1-butene radical cation (CB.+) are only deactivated via internal conversion. Lifetimes of the t-St.+, c-St.+ and CB.+ D2 states are estimated to be approximately 240, 120 and 380 ps, respectively. (author). 4 refs., 1 fig