Resonance lifetime and energy of an excited Cs state on Cu(111)

Abstract

Using time-resolved two-photon photoemission spectroscopy, we investigated the resonance lifetime and energy of an excited Cs state on Cu(111) in the low-coverage case. We found a pronounced lifetime increase of up to 11±3 fs on a copper surface covered with cesium as compared to a clean copper surface in the energy range of an excited electronic Cs state in the spectrum. This result is in agreement with recent theoretical predictions of hybridization among excited atomic levels of alkali atoms near metal surfaces.