arXiv subjects

Britta Ann Johnson

Publications and source records attributed to Britta Ann Johnson.

2 recordsLinked to original sources

arXiv2024

Mean-Field Ring Polymer Rates Using a Population Dividing Surface

Mean-field Ring Polymer Molecular Dynamics (MF-RPMD) offers a computationally efficient method for the simulation of reaction rates in multi-level systems. Previous work has established that, to model a nonadiabatic state-to-state reaction accurately, the dividing surface must be chosen to explicitly sample kinked ring polymer configurations where at least one bead is in a different electronic state than the others. Building on this, we introduce a population difference coordinate and a kink-constrained dividing surface, and we test the accuracy of the resulting mean-field rate theory on a series of linear vibronic coupling model systems as well as spin-boson models. We demonstrate that this new MF-RPMD rate approach is efficient to implement and quantitatively accurate for models over a wide range of driving forces, coupling strengths, and temperatures.

physics.chem-ph↗

arXiv2021

A Skew Dividing Surface for Accurate Nonadiabatic Mean-Field Ring Polymer Rates

Mean-Field Ring Polymer Molecular Dynamics (MF-RPMD) is a powerful, efficient, and accurate method for approximate quantum dynamic simulations of multi-level system dynamics. Initial efforts to compute nonadiabatic reaction rates using MF-RPMD were not successful; recent work showed that this can be remedied by including a simple, if adhoc, correction term that accounts for the formation of `kinked' or mixed electronic state ring polymer configurations. Here, we build on this idea, introducing a electronic state population based reaction coordinate and novel skew dividing surface that constrains nuclear positions to configurations where the reactant and product state potentials are near-degenerate and that samples kinked electronic state configurations. We then demonstrate the numerical accuracy of this method in computing rates for a series of nonadiabatic model systems.

physics.chem-ph↗