Paper SS+AS-WeA7
An Accurate Full-Dimensional Potential Energy Surface for H at Au(111): The Importance of Nonadiabatic Electronic Excitation in Energy Transfer and Adsorption

Wednesday, October 21, 2015, 4:20 pm, Room 112

We have constructed a potential energy surface (PES) for H atoms interacting with fcc gold based on the form of the PES in Effective Medium Theory. The PES was adjusted to match energies calculated by DFT in many configurations, including many with the Au atoms displaced from their lattice positions. It describes both the interatomic forces and electron densities in full dimension with the accuracy of the ab initio energies used in its construction. Calculations describing the motion of H and Au atoms using this full dimensional adiabatic PES agree with results obtained previously using Ab Initio Molecular Dynamics, demonstrating the accuracy of the PES for configurations occurring in the scattering of H atoms from a surface at finite temperature.

The analytic expression for the total energy contains the embedded electron density leading to a self-consistent approach to simulating nonadiabatic trajectories. We find that nonadiabatic electron-hole pair excitation is the most important energy loss pathway for the H atom. The calculated energy distributions for scattered H atoms are in reasonable agreement with experimental results that are just becoming available. and determines the probability and mechanism for its adsorption. Analysis of trajectories calculated with and without nonadiabatic energy dissipation shows the adsorption or sticking probability as well as the mechanism of H atom adsorption is changed dramatically by nonadiabatic energy transfer