Ultra-fast solvation and electron transfer dynamics in dipolar liquids

Abstract

A recently developed microscopic theory of ultra-fast solvation dynamics of an ion in dipolar liquid is briefly reviewed. The theory has been applied to explain observed solvation dynamics in liquid water and acetonitrile.For both these liquids. the calculated solvation time correlation function shows an ultra-fast Gaussian decay which is followed by an exponential-like. much slower. decay. The interesting fact is that the initial Gaussian decay dominates the relaxation to the extent that it contributes about 60-80% to the total decay. These resultsare in excellent agreement with all the available computer simulation and experimental results. We find that both the rotational and the translational librational modes of water contribute significantly to the initial Gaussian decay. Since electron transfer reactions are often controlled by the solvation (as in the Marcus theory).we have carried out a detailed analysis of the dynamic effects of the ultra-fast solvation on electron transfer reactions in the above liquids. It is found that the ultra-fast solvation can have novel effects on the Tales of eleclron-transfer reactions in these liquids.