Excitation of Fe and Cu sputtered from compounds holding different electronic core configurations

Abstract

Some chemical compounds of either copper or iron have been bombarded with 80 keV Ar + ions, and the excitation of sputtered particles has been studied with the use of optical spectrometry. The scope was primarily to study whether the initial charge state (i.e. valence) of the metal element in the undisturbed compound influences the excitation process. All data have been taken at dynamic equilibrium conditions. It is found that the relative line intensities of different core configurations depend only weakly on the valence of the metal in the undisturbed compound. As an example, for sputtering of excited, neutral Cu, the relative distribution of excitation among levels of core configurations 3d 9 and 3d 10 does not depend on whether the copper atoms initially have core configuration 3d 9 (i.e. divalent as e.g. in CuCl 2 ) or 3d 10 (monovalent as in CuCl). Actually, for both cases the relative line intensitive are very close to those obtained with a pure, elemental Cu target. The results are compatible with previous findings, that when a composite targe is bombarded for such a long time that steady-state conditions are reached, the surface region of the target will be so depleted in the electronegative element that it is almost metallic.