Wave packet propagation study of the charge transfer interaction in the F--Cu(111) and -Ag(111) systems

The electron transfer between an F- ion and Cu(1 1 1) and Ag(1 1 1) surfaces is studied by the wave packet propagation (WPP) method in order to determine specifics of the charge transfer interaction between the negative ion and the metal surface due to the projected band gap. A new modeling of the F- ion is developed that allows one to take into account the six quasi-equivalent electrons of F- which are a priori active in the charge transfer process. The new model invokes methods of constrained quantum dynamics. The six-electron problem is transformed to two one-electron problems linked via a constraint. The projection method is used to develop a WPP subject to the modeling constraint. The characteristics (energy and width) of the ion F- ion level interacting with the two surfaces are determined and discussed in connection with the surface projected band gap. (C) 2001 Elsevier Science B.V. All rights reserved.