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The Ge(111)-I surface has been studied at different I coverages ranging from 0.05 ML up to saturation, and different annealing temperatures, using photoelectron spectroscopy (PES) and scanning tunneling microscopy (STM). At saturation the surface is covered with I in the top site and GeI2 species in the bridge site, coexisting with small islands/clusters comprising GeI2, giving a total coverage of I in GeIx species of 1.15 ML. The chemically induced shifts in the Ge 3d core level are 0.39 eV per attached I atom. The coverage determined from the I 4d core level is higher than 1.15 ML, which we explain by the presence of I not bound to Ge. Annealing at 200°C decreases the iodine coverage, whereas the I 4d and Ge 3d line profiles are practically unchanged. Further heating desorbs the iodide species and restores the virgin c(2 × 8) structure.

The growth of silver on Si(111) is reexamined and new experiments are carried out using the method of isothermal desorption spectroscopy with AES. A correlation between LEED patterns and AES data upon adsorption and desorption permits one to precise the domain of existence of both 3 × 1 and √3 phases (respectively completed at 1 3 and 2 3 of a monolayer) and therefore to draw a 2D phase diagram and propose new structural models. We extend a kinetic model proposed earlier for the case of desorption of 2D phases, to the desorption of 3D crystallites. We thus show that using a simple kinetic method, thermodynamic parameters may be directly derived, namely the cohesive energy and the vibrational frequency of each phase. The values obtained, close to the ones of bulk silver, are respectively: E = 68 kcalmole−1, ν = 2.3 × 1012s−1 for the 3 × 1 phase; E = 65 kcalmole−1, ν = 1.8 × 1012s−1 for the √3 phase; E = 67 kcalmole−1, ν = 4 × 1012s−1 for the 3D crystallites.