Nonadiabatic reactive scattering of hydrogen on different surface facets of copper

Stark, Wojciech G. and Box, Connor L. and Sachs, Matthias and Hertl, Nils and Maurer, Reinhard J. (2025) Nonadiabatic reactive scattering of hydrogen on different surface facets of copper. Physical Review B, 112 (3): 035422. ISSN 2469-9950

Abstract

Dissociative chemisorption is a key process in hydrogen-metal surface chemistry, where nonadiabatic effects caused by low-lying electron-hole-pair excitations may affect reaction outcomes. Molecular dynamics with electronic friction simulations can capture weak nonadiabatic effects at metal surfaces, but require energy landscapes and electronic friction tensors as input. Here, we present full-dimensional machine learning surrogate models of the electronic friction tensor to study reactive hydrogen chemistry at the low-index surface facets Cu(100), Cu(110), Cu(111), and Cu(211). We combine these surrogate models with machine learning interatomic potentials to simulate quantum-state-resolved H2 reactive scattering on pristine copper surfaces. The predicted sticking coefficient and survival probabilities are in excellent agreement with experiments. Comparison between adiabatic and nonadiabatic simulations reveals that the influence of electron-hole pair excitations on the scattering dynamics is weak, and that the probability for dissociative adsorption is dominated by the shape of the underlying potential energy surface and the initial vibrational quantum state. Nonadiabatic effects only lead to subtle changes in rovibrationally inelastic state-to-state scattering probabilities. The differences between jellium-based isotropic local density friction and full ab initio response-theory-based orbital-dependent friction are even more subtle. The presented machine learning models represent the most accurate publicly available, full-dimensional models for H2 on copper to date.