ON THE EQUILIBRIUM SEGREGATION OF INTERACTING IMPURITY ATOMS TOWARDS (100) METAL-SURFACES .2. COMPARISON OF THEORETICAL CONSIDERATIONS WITH SELECTED EXPERIMENTAL RESULTS

The calculated bulk isosteres for the segregation of strongly interacting atoms towards (100)-faces of cubic metals are compared to selected experiments on single crystals. From the fit values of the interaction enthalpies between nearest and second neighbors are deduced. It turns out that in order to achieve a satisfactory agreement between measured and calculated bulk isosteres it is often necessary to deviate from the published values of bulk concentrations. Plausible reasons for this are depletion of the impurity atoms during the sample cleaning cycle and (in the case of N/Fe(100)) a gas-solid equilibrium which brings a temperature dependence of the bulk concentration overruling the initial constant value.