MEMORY EFFECTS IN ARRHENIUS BARRIERS FOR SURFACE-DIFFUSION

The importance of memory effects in Arrhenius surface diffusion barrie rs E-A is studied within the lattice-gas model. It is found that E-A o f tracer diffusion is strongly affected by memory effects at finite co verages and low temperatures, where about 10-50% of E-A arises from te mperature variations in the memory effects. In the Arrhenius barrier o f collective diffusion, the memory contribution is also significant bu t less pronounced than in tracer diffusion. Interpretation of E-A's in terms of microscopic activation processes is further discussed. (C) 1 998 Elsevier Science B.V. All rights reserved.