Path integral molecular dynamics with surface hopping for thermal equilibrium sampling of nonadiabatic systems
This work addresses the challenge of thermal equilibrium sampling in nonadiabatic systems, offering a novel approach for quantum chemistry and condensed matter physics.
The authors propose a ring polymer representation for multi-level quantum systems that preserves electronic state discreteness, and develop a path integral molecular dynamics with surface hopping (PIMD-SH) method to sample thermal equilibrium distributions. The method is validated theoretically and through numerical examples.
In this work, a novel ring polymer representation for multi-level quantum system is proposed for thermal average calculations. The proposed presentation keeps the discreteness of the electronic states: besides position and momentum, each bead in the ring polymer is also characterized by a surface index indicating the electronic energy surface. A path integral molecular dynamics with surface hopping (PIMD-SH) dynamics is also developed to sample the equilibrium distribution of ring polymer configurational space. The PIMD-SH sampling method is validated theoretically and by numerical examples.