SEMIEMPIRICAL APPROACHES OF SURFACE PHENOMENA - PT AND NI ADATOMS ON PT(111) AND NI(111)

Two semi-empirical methods, the equivalent crystal theory (ECT) and th e embedded atom method (EAM), were applied to determine adsorption ene rgies of Ni and Pt adatoms on Ni(111) and Pt(111), respectively. This permitted a comparison between the two techniques, which turn out to b e rather equivalent, provided that the peculiarity of the adsorbate-su rface interaction was taken into account in ECT. For the two metals, t he adsorption energy decreases from ternary to bridge and top sites. M oreover, the results could be favourably compared with those given by the extended Huckel method. This is the first use of ECT for adsorptio n study.