The journal of physical chemistry letters | 2019

Ensemble-Based Molecular Simulation of Chemical Reactions under Vibrational Non-Equilibrium.

 
 
 

Abstract


We present an approach to incorporate the effect of vibrational non-equilibrium in molecular dynamics (MD) simulations. A perturbed canonical ensemble-in which selected modes are excited to higher temperature while all others remain equilibrated at low temperature-is simulated by applying a specifically tailored bias potential. Our method can be readily applied to any (classical or quantum mechanical) MD setup at virtually no additional computational cost, and allows to study reactions of vibrationally excited molecules in non-equilibrium environments such as plasmas. In combination with enhanced sampling methods, the vibrational efficacy and mode selectivity of vibrationally stimulated reactions can then be quantified in terms of chemically relevant observables, such as reaction rates and apparent free energy barriers. We first validate our method for the prototypical hydrogen exchange reaction and then show how it can capture the effect of vibrational excitation on a symmetric SN2 reaction and radical addition on CO2.

Volume None
Pages None
DOI 10.1021/acs.jpclett.9b03356
Language English
Journal The journal of physical chemistry letters

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