Femtosecond time-resolved photoemission of electron dynamics in surface
Rydberg states
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A, 15 (3, 2):
1503-1509 (May 1997)43rd American-Vacuum-Society Symposium, PHILADELPHIA, PA, OCT 14-18,
1996.DOI: {10.1116/1.580570}
Abstract
Femtosecond time-resolved photoelectron spectroscopy provides a unique
tool to study the dynamics of optically excited electrons at surfaces
directly in the time domain. We present a new model for two-photon
photoelectron spectroscopy from surface and image potential (or Rydberg)
states which is based on density matrix theory. The formalism accounts
for the influence of both energy and phase relaxation on experimental
spectra and thus permits the study of the nature of inelastic and
elastic scattering processes at surfaces in more detail. The analysis of
experimental data employing the proposed model reveals a new mechanism
for optical excitation of electrons to normally unoccupied states at
surfaces which is feasible due to the influence of electronic dephasing.
We discuss the nature of different relaxation channels with respect to
our studies of image state dynamics on the bare and Xe or Kr covered
Cu(lll) surfaces. (C) 1997 American Vacuum Society.