Implementation of quantum-classical mapping approaches for nonadiabatic molecular dynamics in the PySurf package

01 April 2025, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Quantum-classical methods for nonadiabatic molecular dynamics, based on the Mayer-Miller-Stock-Thoss mapping, are implemented in the open source computer package PySurf. This complements the implementation of surface hopping approaches performed in previous works, and leads to a unified code that allows nonadiabatic dynamics simulations using various mapping approaches (Ehrenfest dynamics, the linearized semiclassical initial value representation, the Poisson-bracket mapping equation, the “unity” approach for the indentity operator, and the spin mapping method) as well as different flavours of surface hopping (fewest-switches, Landau-Zener, and a mapping-inspired scheme). Furthermore, a plugin is developed to provide diabatic vibronic models in a sum-of-products form. This opens the way to the benchmark of different types of quantum-classical propagators on different models, against exact quantum dynamical simulations performed, e.g., by the multiconfigurational time- dependent Hartree method. Illustrative calculations, performed using the whole set of available propagators, are presented for different harmonic and anharmonic two-state models, exhibiting various degrees of correlation between vibrational modes.

Keywords

Nonadiabatic dynamics
Quantum-classical dynamics
Surface hopping
Ehrenfest
Mapping approaches
Quantum dynamics
Photochemistry

Supplementary materials

Title
Description
Actions
Title
Supplementary Information
Description
Derivation of Eqs. (24) and (25) of the main manuscript, and addition computational details of the simulations.
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.