Path-integral isomorphic Hamiltonian for including nuclear quantum effects in non-adiabatic dynamics
Abstract
We describe a path-integral approach for including nuclear quantum effects in non-adiabatic chemical dynamics simulations. For a general physical system with multiple electronic energy levels, a corresponding isomorphic Hamiltonian is introduced such that Boltzmann sampling of the isomorphic Hamiltonian with classical nuclear degrees of freedom yields the exact quantum Boltzmann distribution for the original physical system. In the limit of a single electronic energy level, the isomorphic Hamiltonian reduces to the familiar cases of either ring polymer molecular dynamics (RPMD) or centroid molecular dynamics Hamiltonians, depending on the implementation. An advantage of the isomorphic Hamiltonian is that it can easily be combined with existing mixed quantum-classical dynamics methods, such as surface hopping or Ehrenfest dynamics, to enable the simulation of electronically non-adiabatic processes with nuclear quantum effects. We present numerical applications of the isomorphic Hamiltonian to model two- and three-level systems, with encouraging results that include improvement upon a previously reported combination of RPMD with surface hopping in the deep-tunneling regime.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 12, 2017
- Source ID
- 10.1063/1.5005544
Entities
People
- Philip Shushkov
- Thomas Miller
- Xuecheng Tao
Organizations
- Air Force Office of Scientific Research
- California Institute of Technology
- Office of Naval Research