Molecular Dynamics Study of Plasmon-Mediated Chemical Transformations

TL;DR

This study uses advanced molecular dynamics simulations to explore how plasmon excitation in gold-CO systems facilitates chemical transformations, revealing hot carrier dynamics, charge transfer, and reaction efficiency.

Contribution

It introduces a trajectory surface hopping non-adiabatic molecular dynamics method to analyze plasmon-mediated reactions at an atomistic level, providing new insights into the underlying mechanisms.

Findings

Hot carriers transfer between Au20 and CO after plasmon excitation.

Partial charge transfer occurs from Au20 to CO during excitation.

Plasmon-mediated transformation efficiency is approximately 40%.

Abstract

Heterogeneous catalysis of adsorbates on metallic surfaces mediated by plasmon has potential high photoelectric conversion efficiency and controllable reaction selectivity. Theoretical modeling of dynamical reaction processes provides in-depth analyses complementing experimental investigations. Especially for plasmon-mediated chemical transformations, light absorption, photoelectric conversion, electron-electron scattering, and electron-phonon coupling occur simultaneously at different timescales, rendering it very challenging to delineate the complex interplay of different factors. In this work, a trajectory surface hopping non-adiabatic molecular dynamics method is used to investigate the dynamics of plasmon excitation in an Au$_{20}$-CO system, including hot carrier generation, plasmon energy relaxation, and CO activation induced by electron-vibration coupling. The electronic properties indicate that when Au$_{20}$-CO is excited, a partial charge transfer takes place from Au$_{20}$ to CO. On the other hand, the dynamical simulations show that hot carriers generated after plasmon excitation transfer back and forth between Au$_{20}$ and CO. Meanwhile, the C-O stretching mode is activated due to the non-adiabatic couplings. The efficiency of plasmon-mediated transformation ($\sim$40\%) is obtained based on the ensemble average of these quantities. Our simulations provide important dynamical and atomistic insights into plasmon-mediated chemical transformation from the perspective of non-adiabatic simulations.