First-Principles Understanding of Vibrational Energy Transfer in Molecule-Surface Scattering: Both Adiabatic and Nonadiabatic Channels Matter

Abstract

Energy transfer during molecular collisions on metal surfaces plays a pivotal role in a host of critical interfacial processes. Despite significant efforts, our understanding of relevant energy transfer mechanisms, even in an extensively-studied benchmark like NO scattering from Au(111), remains far from complete. To fully disentangle different energy transfer channels, we develop a first-principles nonadiabatic dynamical model that incorporates explicitly all degrees of freedom and the interfacial electron transfer. Our simulations reproduce, for the first time, most experimental observations on vibrational relaxation and excitation of NO molecules under varying initial conditions and clearly elaborate the respective adiabatic and nonadiabatic contributions. This model identifies the direct adiabatic vibration-to-translation coupling as the dominant role of translation, while excluding significant translation-to-electron nonadiabatic coupling. Furthermore, the observed steric effect varying with the initial vibrational state is understood by the change of orientational dependence of the metal-to-molecule electron transfer. These new insights highlight the importance of treating both adiabatic and nonadiabatic energy transfer pathways on an equal footing, offering significant implications for modeling energy transfer processes in more complex systems, such as plasmonic photocatalysis.