EFFECT OF SOLVENT POLARITY ON THE POTENTIAL OF MEAN FORCE BETWEEN 2 MOLECULAR-IONS - MD SIMULATION

MD simulations with the two-constraint umbrella sampling method have b een applied in calculations of the potential of mean force (PMF) betwe en N,N-dimethylaniline cation (DMA(+)) and anthracene anion (AN(-)) in solvents of high and low polarity (acetonitrile and cyclohexane) at r oom temperature. Relation between quenching of the photoexcited AN vi a electron transfer from DMA and the exciplex formation for solvents o f different polarity has been considered by comparing the two PMFs. Ap plicability of the primitive model of ions and the dielectric continuu m model of the solvent, usually employed in calculations of the intera ction energy between two solutes, is discussed. (C) 1998 Elsevier Scie nce B.V. All rights reserved.