Molecular dynamics study of dipolar relaxation

The equilibrium and nonequilibrium solvation dynamics in a nonspherical and nonpolarizable dipolar liquid around charged solute particles (separated by a distance r = 5 angstrom) is studied by using molecular dynamics. The memory kernel for dielectric friction of the solvent obtained from force-force autocorrelations is analyzed within the framework of Grote-Hynes theory for activated barrier crossing kinetics. The relaxation times of the polarization fluctuations at and around the reactant sites which are needed in the theory of electron transfer proposed by Tembe et al. are evaluated. Solvent dynamics during the process of dielectric relaxation is also studied by using the microscopic and macroscopic dipole-dipole time correlation functions for both equilibrium and nonequilibrium solvation around the reactant ion pair. The nonequilibrium dynamics is also discussed in terms of time-dependent polarization fluctuations in different regions of solvent.