Quenching of the 3B1u→1A1g emission of benzene in low temperature matrices at 10 K

Abstract

The effects of concentration and environment on the triplet state emission of benzene (³B_1u→¹A_1g) have been investigated in low temperature gas matrices at 10 K. For benzene + argon matrices a Monte Carlo calculation of the mean separation between the interacting centres of benzene molecules at the critical concentration has been shown to be 6.5 ± 0.5 Å. The phosphorescence lifetime in a variety of matrices at a concentration beyond the self-quenching limit decreased in the order CH₄ > N₂ > Ar Kr > Xe in accordance with the heavy atom effect which has been noted previously. The fluorescence lifetime of benzene (¹B_2u→¹A_1g) has been measured for the first time in an argon matrix and found to be 45 ± 5 ns for matrix ratios benzene:argon in the range 1 : 20 to 1 : 1000.