Barrier crossing numerical simulation

Molecular dynamic simulations are very useful for solvation dynamic studies. In contrast to the difficulties described in applying numerical methods to the problems of vibrational relaxation (Section 13.6) and barrier crossing (Section 14.7), solvation dynamics is a short-time downhill process that takes place (in pure simple solvents) on timescales easily accessible to numerical work. 

Barrier crossing phenomena are fundamental in chemistry. In many situations barrier crossing events correspond to first-order kinetics characterized by a rate constant. Because the dynamics of such processes corresponds to infrequent events, direct simulation of a reaction from reactants to products can be extremely inefficient- A much better approach is offered by the reactive flux formalism which expresses the reaction rate in terms of the flux crossing a fictitious dividing surface that separates reactants from products. Even though the reactive flux method offers a numerically advantageous approach compared with direct simulation of the reaction itself, fully... 

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