| Abstract
| - We have successfully applied the transition path sampling method to the deterministic dynamics of a many-body system with long-ranged interactions. The process we investigate, dissociation of a model Na+Cl- ionpair in water, involves a wide range of transition pathways in which collective solvent motions play an importantrole. Transition states along these pathways encompass a broad distribution of ionic separations. Ion pairs incontact remain associated for ∼20 ps on average, a time scale considerably longer than the ∼3ps predictedby transition state theory with ionic separation as the order parameter. In contrast to theories of barrier crossingbased upon frictional effects (with or without memory), we find that the discrepancy between these timescales arises from neglected solvent free energy barriers rather than stochastic buffeting of the ion pair.
|
