Techniques for efficiently studying reactive events with electronic structure based biasing and transition path sampling

COMP 199

Christopher N. Rowley, crowle@uwo.ca1, Nicholas J. Mosey, njmosey@uwo.ca1, and Tom K. Woo, twoo@uwo.ca2. (1) Department of Chemistry, University of Western Ontario, 1151 Richmond St., London, ON N6A 5B7, Canada, (2) Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7
In recent years, ab initio molecular dynamics (AIMD) has emerged a powerful tool for studying chemical reactions. However the time-scales that can be studied are limited to the sub-nanosecond regime due to the expensive calculation of the electronic potential energy. Many chemical reactions are rare events on this time-scale, and cannot be studied without special sampling techniques. One solution is to use the electronic structure to bias the simulation to explore reactive events. Another technique is transition path sampling, a Monte Carlo technique developed to efficiently harvest an ensemble of reactive trajectories. This can be used to focus the molecular dynamics simulation on reactive events. We apply these two methods to the study of rare but important chemical events. We will discuss the ability of these methods to treat complex potential energy surfaces and aspects regarding the implementation of these techniques.