Electronic damping of anharmonic adsorbate vibrations at metallic surfaces

Abstract

The nonadiabatic coupling of an adsorbate close to a metallic surface leads to electronic damping of adsorbate vibrations and line broadening in vibrational spectroscopy. Here, a perturbative treatment of the electronic contribution to the lifetime broadening serves as a building block for a new approach, in which anharmonic vibrational transition rates are calculated from a position-dependent coupling function. Different models for the coupling function will be tested, all related to embedding theory. The first two are models based on a scattering approach with ͑i͒ a jellium-type and ͑ii͒ a density functional theory based embedding density, respectively. In a third variant a further refined model is used for the embedding density, and a semiempirical approach is taken in which a scaling factor is chosen to match harmonic, single-site, first-principles transition rates, obtained from periodic density functional theory. For the example of hydrogen atoms on ͑adsorption͒ and below ͑subsurface absorption͒ a Pd͑111͒ surface, lifetimes of and transition rates between vibrational levels are computed. The transition rates emerging from different models serve as input for the selective subsurface adsorption of hydrogen in palladium starting from an adsorption site, by using sequences of infrared laser pulses in a laser distillation scheme.

Role of Tensorial Electronic Friction in Energy Transfer at Metal Surfaces

“…LDFA results for the IS lifetime in literature lie above or below our result, depending on the construction of the embedding density [40,41]. The applicability of LDFA for molecular adsorbates has been a topic of recent discussion [22,27,40].…”

The relationship between the electron work function and friction behavior of passive alloys under different conditions

“…These two surface properties are largely influenced by surface electron activity [3][4][5], which can be reflected by electron work function (EWF, ϕ) [6][7][8]. EWF is the minimum energy required for electrons to escape from the Fermi level inside a metal to a point just outside the metal [9].…”

Toward Detection of Electron-Hole Pair Excitation in H-atom Collisions with Au(111): Adiabatic Molecular Dynamics with a Semi-Empirical Full-Dimensional Potential Energy Surface

“…Note that these DFT energies were not used in the optimization procedure. These sites (labeled [11][12][13][14] are also shown in Fig. 1b.…”