Quantum Dynamics from Classical Trajectories: Direct Simulation of Electron Diffusion, Injection, and Transfer
Abstract: Coupled electronic and nuclear dynamics are a fundamental aspect of key processes in biology and chemistry, including enzyme catalysis and the production of renewable energy. However, efforts to understand these processes demand new theoretical methods that can accurately, efficiently, and robustly describe the coupled electronic and nuclear dynamics in condensed phases systems. In this talk, I will describe our recent extension [1,2] of Ring Polymer Molecular Dynamics (RPMD) for this purpose, including applications to solvated electron diffusion, excess electron injection into liquids, mixed-valence electron transfer, and proton-coupled electron transfer dynamics. RPMD is an approximate quantum dynamics method based on Feynman’s path integral formulation of statistical mechanics. It provides a molecular dynamics model that both preserves the exact quantum Boltzmann distribution and exhibits time-reversible symmetry; these features allow RPMD to be combined with rare event sampling methods and other powerful methods to characterize reaction rates and reaction mechanisms in complex systems.  T. F. Miller, III, "Isomorphic classical molecular dynamics model for an excess electron in a supercritical fluid,” J. Chem. Phys., 129, 194502 (2008).  A. R. Menzeleev and T. F. Milller, III. "Ring Polymer Molecular Dynamics Beyond the Linear Response Regime: Excess Electron Injection and Trapping in Liquids," J. Chem. Phys., in press.