Plasmon-assisted electron capture into multiply-charged Neq+ ions interacting with an Al surface

Low-energy electron emission spectra were measured during the interaction o f 4.5 keV Neq+ ions with an Al surface for incident charge states q = 1-6. Signatures for surface and bulk plasmons were found near 6.5 and 11 eV, res pectively. For Ne with a single or double vacancy in the L-shell the excita tion of plasmons is explained by means of resonant plasmon-assisted electro n capture. For q = 6 the structure attributed to the bulk plasmon disappear s. This disappearance is ascribed to the attenuation of the electrons produ ced in the solid by the plasmon decay. Measurements of the bulk plasmon int ensity for q = 2 as a function of the observation angle support the propose d scenario. (C) 1998 Published by Elsevier Science B.V. All rights reserved .