Free energy is typically referred to as the most important quantity in chemistry, with computational approaches offering unique insight into the effects that govern chemical and biochemical processes. In this work, we introduce a new chain-of-replica method that uses an umbrella sampling-like approach to determine the potential of mean force (PMF) and present examples. The Off-Path Simulation method (OPS) uses multiple distance restraints to sample orthogonal directions of a discretized reference path. Further, we have interfaced this methodology in a fully distributed parallel scheme that loosely couples replicas; this facilitates the study of larger systems with near perfect scalability to thousands of processors. We applied the OPS methodology to calculate the torsional free energy of butane, and the dissaccharide maltose (vacuum and solvated). OPS calculated values were compared to published theoretical work to verify the validityof this new approach.

Off-Path simulation method: A new chain-of-replica approach for sampling reaction processes

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.