Plasmon resonances of Ag(001) and Ag(111) studied by power density absorption and photoyield
Abstract
This paper models the surface and bulk plasmon resonances in photoabsorption and photoelectron spectra (PES) of the Ag(001) and the Ag(111) surfaces in the region of 2.810 eV excited with a p or transverse magnetic linearly polarized laser incident at 45°. Using the recently developed vector potential from electron densitycoupled integrodifferential equations (VPEDCIDE, [1,2]) model, we calculate the electron escaping probability from the power density absorption, Feibelman's parameter d_{⊥}, the reflectance and the Fermi PE cross section. In the PES experiment the work function is lowered from 4.5 to 2.8 eV by adsorption of sodium. In our model, this lowering is introduced by adding a phenomenological term to the DFTLDA model potential of Chulkov et al. [3]. For both Ag(001) and Ag(111), the calculated observables display two plasmon resonances, the multipole surface at 3.70 eV and the bulk at 3.90 eV, in fair agreement with the experimental PES of Barman et al. [4,5] and the reflectance. Except for the Fermi PE cross section of Ag(001) which does not display the multipole surface plasmon resonance at 3.70 eV. This poor result is probably due to a poor calculation of the conduction band wave functions obtained from the Schrödinger equation using the modified DFTLDA model potential of Chulkov et al.
 Publication:

Surface Science
 Pub Date:
 September 2013
 DOI:
 10.1016/j.susc.2013.02.005
 Bibcode:
 2013SurSc.615....6R