Curotto, Roberts ’12 and Sebsbie ’12 Co-Author Article in ‘Journal of Chemical Physics’

By schwartzsa | February 24, 2012

Dr. Emanuele Curotto, Professor and Chair of the Department of Chemistry and Physics, co-authored an article in the Journal of Chemical Physics titled “A rare event sampling method for diffusion Monte Carlo using smart darting.” Chemistry majors Kelsey Roberts ’12 and Rediet Sebsebie ’12 are co-authors. Roberts, who has been accepted into a Ph.D. program at the University of Delaware, will present this work at the Regional Meeting of the American Chemical Society in spring 2012.

Title: A rare event sampling method for diffusion Monte Carlo using smart darting

Authors: K. Roberts, R. Sebsebie, and E. Curotto (2012). Journal of Chemical Physics.

Abstract: We identify a set of multidimensional potential energy surfaces sufficiently complex to cause both the classical parallel tempering and the guided or unguided diffusion Monte Carlo methods to converge too inefficiently for practical applications. The mathematical model is constructed as a linear combination of decoupled Double Wells [(DDW)n]. We show that the set (DDW)n provides a serious test for new methods aimed at addressing rare event sampling in stochastic simulations. Unlike the typical numerical tests used in these cases, the thermodynamics and the quantum dynamics for (DDW)n can be solved deterministically. We use the potential energy set (DDW)n to explore and identify methods that can enhance the diffusion Monte Carlo algorithm. We demonstrate that the smart darting method succeeds at reducing quasiergodicity for n _ 100 using just 1 × 106 moves in classical simulations (DDW)n. Finally, we prove that smart darting, when incorporated into the regular or the guided diffusion Monte Carlo algorithm, drastically improves its convergence. The new method promises to significantly extend the range of systems computationally tractable by the diffusion Monte Carlo algorithm.