Collective diffusion in a lattice-gas: application to O/W(110)

In this paper the diffusion of oxygen on the W(110) surface for coverages theta < 1/8 nd at various temperatures T = 600, 800, 1000 and 1200 K is studied. In particular the energy width of the coherent dynamic structure factor and the chemical diffusion coefficient, which are computed by using the Mori projection operator technique and neglecting memory effects, are presented. The energy width displays a relative minimum at the border of the first Brillouin zone in the direction q = q_x (1, 1/sqrt(2)).