First-principles Nonadiabatic Dynamics of Molecules at Metal Surfaces with Vibrationally Coupled Electron Transfer

TL;DR

This paper develops a neural network-based method to accurately simulate nonadiabatic molecular dynamics at metal surfaces, successfully matching experimental results without empirical parameters.

Contribution

It introduces a high-dimensional neural network diabatic potential combined with mixed quantum-classical surface hopping for first-principles simulations.

Findings

Accurately describes nonadiabatic effects in CO scattering from Au(111).

Reveals energy loss channels in vibrational relaxation of CO.

Shows relaxation varies with vibrational excitation level.

Abstract

Accurate description of nonadiabatic dynamics of molecules at metal surfaces involving electron transfer has been a longstanding challenge for theory. Here, we tackle this problem by first constructing high-dimensional neural network diabatic potentials including state crossings determined by constrained density functional theory, then applying mixed quantum-classical surface hopping simulations to evolve coupled electron-nuclear motion. Our approach accurately describes the nonadiabatic effects in CO scattering from Au(111) without empirical parameters and yields results agreeing well with experiments under various conditions for this benchmark system. We find that both adiabatic and nonadiabatic energy loss channels have important contributions to the vibrational relaxation of highly vibrationally excited CO(vi = 17), whereas relaxation of low vibrationally excited states of CO(vi = 2) is weak and dominated by nonadiabatic energy loss. The presented approach paves the way for accurate first-principles simulations of electron transfer mediated nonadiabatic dynamics at metal surfaces.