Studies of chemical reactions of excited species using intense light sources

The use of measurements of the products of flash photolysis as a means for studying the reactions of electronically-excited molecules is discussed. With intense light sources the problem of isolating these reactions from others involving free radicals is simplified. The flash sources also have their limitations, and misleading information which can result from the presence of inert gases is noted. A diagnostic test is proposed for detecting the effects (if any) of a possible adiabatic temperature rise of the flash. Some recent studies in the author's laboratory are summarized. Evidence is presented that in the flash photolysis of acetone acetyl radicals arise from an excited molecule. Several deactivation processes are described and compared with results from fluorescence studies