THERMAL DESORPTION OF METALS FROM TUNGSTEN SINGLE CRYSTAL SURFACES.

After a short review of the experimental methods used to determine desorption energies E and frequencies nu the assumptions underlying the theoretical analysis of the experimental data are discussed. Then recent experimental results on the flash desorption of Cu, Ag and Au from clean, well characterized W left brace 110 right brace and left brace 100 right brace surfaces are presented and analyzed in detail, in particular with respect to the coverage dependence. The results obtained this way reveal the limitations of previous analysis methods and of the experimental technique per se (such as structure and phase changes below and in the temperature region in which desorption occurs). Furthermore the need for more theoretical work to understand the large changes of nu and E with coverage and the so-called ″compensation effect″ , i. e. the relation between ln nu and E, becomes evident.