Fluorescence of monochlorobenzene in the vapor phase

The vapor phase fluorescence of monochlorobenzene has been measured in the presence of ethane, propane, or n-butane. The excitation wavelength effect on the fluorescence quantum yield indicates that there should be a fast nonradiative decay channel, an intermediate isomer, at around 240 nm. Pressure effect of a foreign gas on the fluorescence quantum yield is also studied and the nonradiative relaxation processes are discussed.