To the theoretical analysis of the work function changes of platinum group metals adsorbed on (110) W

The simple theoretical model based on the Anderson-Newns Hamiltonian is proposed for the description of work function changes for different surface structures of adatoms. The direct exchange interaction of adjacent adatoms is taken into account. The model permits one to calculate values of the adatom dipole moment as a function of the nearest-neighbor adatom's number. This gives some key to the understanding of the variations of adatom structures with temperature and concentration. The numerical calculations are performed for Rh, Lr, and Pt adsorbed on (110)W. (C) 1997 Elsevier Science B.V.