Monte Carlo simulation of orientational effects on direct energy transfer

Abstract

The donor ensemble excitation decay is obtained by a Monte Carlo simulation for the three-dimensional case. Donor and acceptor reorientational motions are explicitly considered within the isotropic diffusion model. Allowance is made for donor and acceptor different rotational rates. The orientation dependent part of the decay is fully contained in the factor 〈(∼(κ2))1/2〉 which is the ensemble average of the square root of the finite time average of the usual orientational factor κ2. The time dependence of 〈(∼(κ2))1/2〉 is evaluated by a Monte Carlo simulation procedure for several relative mobilities of the donor–acceptor pair and finally captured in a simple, one-parameter formula.