Surface characterization by means of quantitative evaluation of MIES data

We review the recent progress in the quantitative evaluation of MIES (Metas table Induced Electron Spectroscopy). We discuss electron spectra taken wit h He*(2(3)S) at several systems. For graphite, it is shown that the surface density of the occupied pi-band as experienced by He*(23S) can be related to the bulk density of states by an analytical, k-vector-dependent, weighti ng function. In the case of adsorbed alkane molecules, it is possible to an alyze the contribution of different molecular orientations to the compositi on of the top surface layer. Double bond formation at hydrocarbon films und er the influence of ion bombardment can be monitored quantitatively as well . Finally, we discover within a series of MIE spectra taken during adsorpti on of NaCl on W(110), a third chemical species in addition to NaCl and meta llic tungsten. We propose that this third species is formed on the border o f NaCl domains. Spectroscopically, it is not a simple addition of salt and metal spectra, but develops its own characteristic features. Even though th is species contributes more than 65% of the MIE signal at intermediate cove rage, it has escaped detection so far. (C) 1998 Elsevier Science B.V. All r ights reserved.