Title: Coherent State Mapping Ring-Polymer Molecular Dynamics for Non-Adiabatic quantum propagations,
Abstract: We introduce the coherent state mapping ring-polymer molecular dynamics
(CS-RPMD), a new method that accurately describes electronic non-adiabatic
dynamics with explicit nuclear quantization. This new approach is derived by
using coherent state mapping representation for the electronic degrees of
freedom (DOF) and the ring-polymer path-integral representation for the nuclear
DOF. CS-RPMD Hamiltonian does not contain any inter-bead coupling term in the
state-dependent potential, which is a key feature that ensures correct
electronic Rabi oscillations. Hamilton's equation of motion is used to sample
initial configurations and propagate the trajectories, preserving the
distribution with classical symplectic evolution. In the special one-bead limit
for mapping variables, CS-RPMD preserves the detailed balance. Numerical tests
of this method with a two-state model system show a very good agreement with
exact quantum results over a broad range of electronic couplings.