MONTE-CARLO SIMULATIONS OF ELECTRONIC EXCITATION TRANSFER IN POLYMER COMPOSITES AND COMPARISON TO THEORY

Monte Carlo (MC) simulations of electronic excitation transfer (EET) a mong a small number of chromophores covalently incorporated into copol ymer molecules are presented and used to test the results of previousl y developed analytical EET theories that are useful for the study of p olymer chain structure [K. A. Peterson and M. D. Fayer, J. Chem. Phys. 85, 4702 (1986)] and phase separation in polymer blends [A. H. Marcus and M. D. Fayer, J. Chem. Phys. 94, 5622 (1991)]. The simulations and theory account for EET among chromophores bound to a single chain and among chromophores attached to different chains. The calculated quant ity, [G(s)(t)], which is the probability that an initially excited chr omophore is still excited at time t, is related to time-resolved fluor escence depolarization experiments. The theories, particularly the tre atment of interchain EET, depend on a series of approximations whose e fficacy has not been determined. Close agreement between the MC simula tions and the analytical theory are found for a variety of situations, including those that mimic real polymer systems. The limits beyond wh ich agreement is weakened provide specific guidelines for the design o f polymer structure and phase-separation experiments. (C) 1998 America n Institute of Physics. [S0021-9606(98)52343-4].