DIFFUSION ON STEPPED SURFACES .3. ENHANCED DIFFUSION ALONG STEP EDGES

The effect of enhanced jump probability in step edge (downside) rows o n adsorbate diffusion was investigated by Monte Carlo simulations, for assumed attractive step adsorption and in the presence and absence of adsorbate nearest-neighbor repulsion. In all cases diffusion parallel to steps is enhanced. The effect is most pronounced at low temperatur es, for NN repulsion. However, the magnitude of the enhancement is rel atively small when the reduction in activation energy for jumps in led ge rows is comparable to step attraction or nearest-neighbor repulsion energies.