# Mode specific electronic friction in dissociative chemisorption on metal surfaces: H$_2$ on Ag(111)

## TL;DR

This study reveals that electronic friction during H₂ dissociation on Ag(111) is highly mode-dependent, with bond stretch vibrations experiencing significant nonadiabatic energy loss, influencing reaction dynamics and energy distribution outcomes.

## Contribution

It introduces a mode-specific electronic friction model evaluated via DFT, highlighting its impact on dissociative chemisorption and reaction steering on metal surfaces.

## Key findings

- Strong mode dependence of electronic friction observed.
- Nonadiabatic energy loss mainly along bond stretch coordinate.
- Friction influences reaction outcomes and energy distributions.

## Abstract

Electronic friction and the ensuing nonadiabatic energy loss play an important role in chemical reaction dynamics at metal surfaces. Using molecular dynamics with electronic friction evaluated on-the-fly from Density Functional Theory, we find strong mode dependence and a dominance of nonadiabatic energy loss along the bond stretch coordinate for scattering and dissociative chemisorption of H$_2$ on the Ag(111) surface. Exemplary trajectories with varying initial conditions indicate that this mode-specificity translates into modulated energy loss during a dissociative chemisorption event. Despite minor nonadiabatic energy loss of about 5\%, the directionality of friction forces induces dynamical steering that affects individual reaction outcomes, specifically for low-incidence energies and vibrationally excited molecules. Mode-specific friction induces enhanced loss of rovibrational rather than translational energy and will be most visible in its effect on final energy distributions in molecular scattering experiments.