Interaction of hydrogen and oxygen with a chlorine covered Ag(111) surface

Results of a study of changes in electron capture and loss rates in the int eraction of hydrogen and oxygen atoms and anions with chlorine covered Ag(1 11) surfaces are reported for a wide range of coverages. Strong oscillatory changes in anion formation rates are observed as a function of chlorine co verage. These: changes are assigned to changes in local electronic structur e and modifications in positions and widths of the anion levels at differen t phases of chlorine adsorption and in particular to interaction of the pro jectile with the adsorbed Cl(3p) levels. At high coverages, a higher electr on capture probability is found, corresponding to the appearance of chlorid e islands. (C) 2001 Published by Elsevier Science B.V.