Nanosecond laser studies of photophysical processes in the benzene + tetracyanobenzene molecular complex

Abstract

A 1 MW pulsed nitrogen gas laser was used to investigate the various photophysical processes operating in the 1, 2, 4, 5-tetracyanobenzene (TCNB)+ benzene molecular complex. These processes were found to be affected by increasing amounts of acetonitrile. In mixtures containing less than 20 % acetonitrile the fluorescent state of the EDA complex was formed with unit probability. However, the relative quantum yield and the lifetime of the fluorescent state was found to decrease as the amount of acetonitrile increased. This was attributed to a decrease in the radiative transition probability and an increase in non-radiative probabilities. At higher acetonitrile concentrations ionisation was the predominant decay mode of the excited state, and the quantum yields of ion production were estimated.