Photophysics of benzene and [2H6]-benzene in frozen gas matrices at 12 K
Abstract
The effect of environment on the photophysics of C6H6 and C6D6 has been studied in low temperature gas matrices (CH4, CF4, N2, CO, SF6, Ar, Kr, Xe). The fluorescence and phosphorescence quantum yields have been determined for the first time and the rates of fluorescence, phosphorescence, intersystem crossing and radiationless decay from the triplet state calculated. The rate constants of fluorescence and intersystem crossing in CH4 matrices at 12 K and in solution and gas phases at 300 K are similar in magnitude. The external heavy-atom effect has been shown to enhance S1→T1 intersystem crossing in Ar matrices and the quenching of phosphorescence in CO matrices is interpreted as being due to complex formation. In all cases the effect of perdeuteriation is to reduce the calculated rate constants, which is consistent with a reduction in the Franck–Condon factors.