Microwave effect on a pulse-excited prompt fluorescence of molecular crystals

Abstract

The influence of a microwave radiation on the prompt fluorescence (PF) excited in molecular crystals by an ultrashort laser pulse is theoretically considered in the work. Laser pulse excites organic molecule to the lowest singlet state S1 and simultaneously produces a pair of localized triplet excitons in its singlet state. The subsequent emission from the S1 level and emission from the singlet spin component of the triplet pair combine to produce PF. Unlike the steady-state RYDMR, the pulsed method proposed in this work allows the two emission channels to be discriminated. A microwave-induced contribution to the PF-decay curve is shown to be bell-shaped and contain oscillatory component. By measuring the amplitude of these oscillations one can estimate relationship between the partial transition rates controlling the decay process.