DETERMINATION OF THE ACCEPTOR MOLECULES CONCENTRATION IN THE TRIPLET STATE ON EXCITATION OF DONOR-ACCEPTOR PAIRS BY RECURRENT PULSES

Abstract

Analysis of population and decay of excited states play an important role in the study of photophysical processes. Information on the accumulation of organic molecules in triplet state is contained in the phosphorescence buildup kinetics. The possibility of determining of the concentration of the energy-acceptor molecules in the triplet state from kinetic experiments has been investigated in the paper. The sensitized excitation of molecules by means of the transfer of triplet excitations by the exchange-resonance mechanism has been considered. It is shown that the buildup of acceptor sensitized phosphorescence can be described by exponential function when excitation created by means of phosphoroscope. Expressions, allowing to calculate the concentration of molecules in the triplet state have been obtained. The time of accumulation of the acceptor molecules in the triplet state was determined from experimental curve of sensitized phosphorescence buildup. The obtained time of phosphorescence buildup allowed to find the concentration of the acceptor molecules in the triplet state.