Effect of solvent on the subnanosecond decay of the second excited singlet state of tetramethylindanethione

Abstract

The S 2 → S 0 fluorescence spectra and quantum yields and the S 2 lifetimes of 2,2,3,3-tetramethylindanethione (TMIT) have been measured in several solvents using a synchronously pumped picosecond dye laser excitation system. The S 2 nonradiative decay rate is markedly solvent dependent. In inert perfluoroalkane solvents remarkably large S 2-S 0 fluorescence quantum yields (θ f = 0.14) and long S 2 lifetimes (τ = 880 ps) are measured. Hydrocarbons are efficient excited-state quenchers.