Energy transfer and orientational dynamics in isotropic and nematic phases. A computer simulation approach

We present a computer simulation study of the effect of molecular reorientation on the Fِrster-type energy transfer (ET) process in a nematic and isotropic phase. Monte Carlo (MC) equilibrium configurations and a stepwise diffusion algorithm are employed to model the ET process and the molecular rotational dynamics in the case of arbitrary time scales. We find faster fluorescence depolarization at higher rotational dynamic rates, but the transfer efficiency and directionality observed for fixed molecules is also maintained in the presence of molecular reorientation.