On the calculation of reaction rate constants in the transition path ensemble

We present improved formulas for the calculation of transition rate constan ts in the transition path ensemble. In this method transition paths between stable states are generated by sampling the distribution of paths with a M onte Carlo procedure. With the new expressions the computational cost for t he calculation of transition rate constants can be reduced considerably com pared to our original formulation. We demonstrate the method by studying th e isomerization of a diatomic molecule immersed in a Weeks-Chandler-Anderse n fluid. The paper is concluded by an efficiency analysis of the path sampl ing algorithm. (C) 1999 American Institute of Physics. [S0021-9606(99)50513 -8].