COMPUTER-SIMULATION STUDIES OF SOLVENT EFFECT ON ELECTRON-TRANSFER INACETONITRILE SOLUTIONS

The Molecular Dynamics method of computer simulation has been applied to evaluate the statistical distribution of the electrostatic potentia l difference e Delta V between donor and acceptor sites immersed in ac etonitrile solvent. By using this distribution the electron transfer r ate constant for considered molecular systems has been calculated as a function of the free energy change of the reaction, Delta G. This dep endence has been compared with the corresponding result calculated on the basis of the dielectric continuum model. It appears that a molecul ar model of solvent causes the shift of the inverted region for the ch arge separation reaction towards more negative values of Delta G. Cons equently, the inverted region starts in the range of Delta G which is not accessible by experimental measurements. An estimation of the quan tum correction to the potential difference distribution has been also performed. The correction calculated using the time correlation functi on of fluctuations in e Delta V is found negligible.