Real-Time Observation of Adsorbate Atom Motion Above a Metal Surface

Abstract

The dynamics of cesium atom motion above the copper(111) surface following electronic excitation with light was studied with femtosecond (10(-15) seconds) time resolution. Unusual changes in the surface electronic structure within 160 femtoseconds after excitation, observed by time-resolved two-photon photoemission spectroscopy, are attributed to atomic motion in a copper-cesium bond-breaking process. Describing the change in energy of the cesium antibonding state with a simple classical model provides information on the mechanical forces acting on cesium atoms that are "turned on" by photoexcitation. Within 160 femtoseconds, the copper-cesium bond extends by 0.35 angstrom from its equilibrium value.

Decay of electronic excitations at metal surfaces

“…1). The inelastic channel gives similar contributions in both cases leading to values of lifetimes that are in reasonable agreement with the experimental values [281][282][283][284]287]. A theoretical study, together with a comparison of the available experimental data, of the lifetime of electronically excited states in the Na, K, Rb, Cs/Cu(1 1 1) systems has been made by Borisov et al [328].…”

“…Due to the long time it takes for the excitation to delocalize [286], the beginning of desorption could be monitored for this system. It manifests itself in a time-dependent shift of the energy of the 6s-derived state and a non-exponential decay [287,288].…”

Hot Adsorbate-Induced Retardation of the Internal Thermalization of Nonequilibrium Electrons in Adsorbate-Covered Metal Nanoparticles

“…12,13 More specifically, the dynamical behavior of nonequilibrium electrons (NEs) governs the yield of hot electron-mediated surface reactions on metal surfaces. [14][15][16] The hot electron cooling dynamics 17 as well as the mechanism of breathing modes excitation 18 has already been reported for gold NPs. At present, the internal thermalization dynamics has been mainly investigated in bulk metals [19][20][21] and naked metal nanoparticles.…”

Self-consistent approach for spectral properties of single alkali adatoms on Cu(111)

“…[40][41][42] A long decay time is relevant for physical processes exploiting the alkali resonance as transient state, for example, increasing the efficiency of photo-induced desorption processes. 62,63 Angleand time-resolved photoemission experiments (AR-2PPE, TR-2PPE) characterized also a second resonance, at higher energies with respect to the σ one, which displays a maximum in intensity off-normal and has been thus identified as a π resonance (m = 1). 64 For what concerns the theoretical studies, different approaches can be found in the literature.…”