Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 42: Electron-driven Processes

O 42.6: Talk

Tuesday, March 18, 2025, 15:15–15:30, H11

Electronic friction simulations of laser-driven hydrogen evolution from copper. Just thermal desorption in a hurry? — •Alexander Spears, Wojciech G Stark, and Reinhard J. Maurer — University of Warwick, Coventry, UK

Ultrafast light pulses can induce energy transfer between light, electrons, and phonons at interfaces, leading to ultrafast dynamics such as light-driven hydrogen evolution from metal surfaces. Whether this energy transfer can drive photocatalysis through selective energy transfer into certain degrees of freedom remains an open question. Molecular dynamics simulations with electronic friction (MDEF) offer a quantum-classical description of electron-phonon coupling and have previously been used to model ultrafast surface dynamics. However, the effect of different electronic friction approximations on the final energy distributions has not been thoroughly investigated. We present MDEF simulations of light-driven hydrogen evolution from different copper surface facets, enabled by machine-learning surrogate models. For various laser fluences, we study desorption probabilities and final state distributions of desorbed molecules. Our results reveal that the choice of electronic friction approximation significantly affects desorption probabilities. However, the magnitude and nature of friction do not seem to affect the final vibrational, rotational, and translational energy distribution of molecular adsorbates. Within the electronic friction approximation, only the shape of the energy landscape determines these properties and no selective energy transfer occurs. This suggests that thermal and laser-driven desorption may yield similar outcomes.

Keywords: photocatalysis; ultrafast dynamics; electron-phonon coupling; machine learning