Features of molecules accumulation in the triplet state at excitation of the organic compounds by rectangular pulses

Abstract

Theoretical research of the time dependence on molecules concentration in triplet state under excitation organic compounds have been carried out by light pulses with high. The computer simulation of the molecular dependence on the triplet level population of time during the excitation pulse and after its ending have been realized by using the obtained analytic expressions. It is shown that for a certain relation between the rate constants of intra molecular transitions and the excitation pulse duration, the triplet level population can increase several times after excitation ending. It is due to the transition of molecules which it were in the excited singlet state at the end of the excitation pulse to the triplet state. Note that this effect must be considered in the study of dynamic of photo physical processes and photochemical reactions taking place with the participation of triplet states of organic molecules when they are excited by short light pulses of high intensity.