MONTE-CARLO SIMULATION OF BIOMOLECULAR EXCITON ANNIHILATION IN AN ENERGETICALLY RANDOM HOPPING SYSTEM

The kinetics of bimolecular annihilation of neutral excitations in hop ping systems in which the energy of the hopping sites varies according to a Gaussian distribution has been studied employing Monte Carlo sim ulation techniques. A transition from dispersive to non-dispersive rea ction kinetics is observed, the former giving rise to a reaction law d n/dt is-proportional-to t-1. For times exceeding the energetic relaxat ion time of the excitations the classic dn/dt is-proportional-to t-2 b ehaviour is approached. The dependence of the bimolecular recombinatio n coefficient on both time and temperature parallels that of the diffu sivity of non-interacting excitations.