Cavity-bias sampling in reaction ensemble Monte Carlo simulations

Abstract

A methodology is presented to sample efficiently configurations of reacting mixtures in the reaction ensemble Monte Carlo simulation technique. A cavity-biasing scheme is used, which more effectively samples configurations than conventional random sampling. Akin to other biasing schemes that are implemented into insertion-based Monte Carlo methods such as Gibbs ensemble Monte Carlo, the method presented here searches for space in the reacting mixture whereby the insertion of a product molecule is energetically favoured. This sampling bias is then corrected in the acceptance criteria. The approach allows for the study of reacting mixtures at high density as well as for polyatomic molecular species. For some cases, the method is shown to increase the efficiency of the reaction steps by a factor greater than 20. The approach is shown to be readily generalized to other biasing schemes such as orientational-biasing of polar molecules and configurational-biasing of chain-like molecules.

Acknowledgements

The author wishes to thank Martin Lísal (Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic) and Betsy M. Rice (US Army Research Laboratory) for helpful discussions and critical reading of this manuscript prior to publication. This work was performed while J.K.B. held a National Research Council Research Associateship Award at the US Army Research Laboratory. The calculations reported in this work were performed at the Army Research Laboratory Major Shared Resource Centre, Aberdeen Proving Ground, MD.

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Additional information

Notes on contributors

J. K. Brennan*

Email: [email protected]