Electron-transfer processes in the interaction of fluorine with a chlorine-covered Ag(111) surface

Results of a study of changes in electron capture and loss rates in the int eraction of fluorine atoms and anions with chlorine-covered Ag(111) surface s are reported for a wide range of coverages. A strong decrease in F- forma tion is observed at low-coverage, chemisorption conditions. The magnitude o f this decrease shows that electron capture and loss rates are different fr om those expected on the basis of workfunction changes only. The observed d ecrease is assigned to changes in local electronic structure at and in the vicinity of the adsorbate site and modifications in positions and widths of the anion levels. At high coverages a higher electron-capture probability is found, corresponding to the appearance of chloride islands. (C) 2000 Pub lished by Elsevier Science B.V. All rights reserved.