Pi resonance of chemisorbed alkali atoms on noble metals.
We have performed a joint experimental and theoretical study of the unoccupied electronic structure of alkali adsorbates on the (111) surfaces of Cu and Ag. Combining angle- and time-resolved two-photon photoemission spectroscopy with wave packet propagation calculations we show that, along with the well known sigma resonance oriented along the surface normal, there exist long-lived alkali-localized resonances oriented parallel to the surface (pi symmetry). These new resonances are stabilized by the projected band gap of the substrate and emerge primarily from the mixing of the p and d Rydberg orbitals of the free alkali atom modified by the interaction with the surface.
Borisov
A G
AG
Laboratoire des Collisions Atomiques et Moléculaires, UMR CNRS-Universite Paris-Sud 8625, Bâtiment 351, Université Paris-Sud, 91405 Orsay cedex, France. andrei.borissov@u-psud.fr
Sametoglu
V
V
Winkelmann
A
A
Kubo
A
A
Pontius
N
N
Zhao
J
J
Silkin
V M
VM
Gauyacq
J P
JP
Chulkov
E V
EV
Echenique
P M
PM
Petek
H
H