Nonadiabatic Quantum Dynamics of Molecules Scattering from Metal Surfaces

TL;DR

This paper introduces a comprehensive quantum dynamical method for simulating molecule-metal surface scattering, capturing nonadiabatic and quantum nuclear effects, and benchmarks various approximate methods against it.

Contribution

It develops a hierarchical equations of motion approach combined with matrix product states to accurately model nonadiabatic molecular scattering from metal surfaces.

Findings

Successfully applied to nitric oxide scattering from Au(111)

Captured experimentally observed energy loss during scattering

Provided benchmarks for approximate quantum-classical methods

Abstract

Nonadiabatic coupling between electrons and molecular motion at metal surfaces leads to energy dissipation and dynamical steering effects during chemical surface dynamics. We present a theoretical approach to the scattering of molecules from metal surfaces that incorporates all nonadiabatic and quantum nuclear effects due to the coupling of the molecular degrees of freedom to the electrons in the metal. This is achieved with the hierarchical equations of motion (HEOM) approach combined with a matrix product state representation in twin space. The method is applied to the scattering of nitric oxide from Au(111), for which strongly nonadiabatic energy loss during scattering has been experimentally observed, thus presenting a significant theoretical challenge. Since the HEOM approach treats the molecule-surface coupling exactly, it captures the interplay between nonadiabatic and quantum nuclear effects. Finally, the data obtained by the HEOM approach is used as a rigorous benchmark to assess various mixed quantum-classical methods, from which we derive insights into the mechanisms of energy dissipation and the suitable working regimes of each method.