Using multi-state transition filtering to improve the accuracy of expectation values via mixed quantum-classical Liouville dynamics

Abstract

Recently, we developed a transition filtering approach for reducing the number of trajectories required in computations of time-dependent expectation values via mixed quantum-classical Liouville dynamics. This approach was successfully applied to the two-state spin-boson model, with an order of magnitude reduction in the number of trajectories. In this study, we propose an improved version of this scheme for treating multi-state systems with more than two states and apply it to a three-state model of a condensed phase proton-coupled electron transfer reaction. Our results are compared to the exact quantum mechanical results and to those obtained using alternate filtering schemes. Using the new approach, we obtain a significant improvement in the accuracy of the results, with fewer trajectories as compared to the other schemes.