Transition path sampling: throwing ropes over mountains in the dark

. Understanding rare transitions occurring in complex systems, for instance chemical reactions in solution, poses the problem of finding and analysing the trajectories that move from one basin of attraction to another on a complicated potential energy surface. We have developed a systematic approach for finding these trajectories using computer simulations without preconceived knowledge of transition states. The approach follows from a novel statistical mechanics and thermodynamics of trajectories and has been demonstrated with several applications. (Some figures in this article appear in black and white in the printed version.) 1. Introduction We have developed a general computational method, called transition path sampling, for finding rare pathways connecting stable states in complex systems [1--5]. This method allows one to study, for instance, chemical reactions in solution or conformational transitions of large biopolymers. The algorithm requires no preconceived notion of mech...