Diffusion of Particles Adsorbed on a Reconstructive Surface
The influence of surface reconstruction on diffusion of particles, adsorbed on the surface, is investigated in the framework of symmetrical four-position model. The analytical expressions for the free energy and chemical and jump diffusion coefficients are obtained assuming the lateral interaction between the particles is negligibly small. The coverage dependencies of the tracer, jump and chemical diffusion coefficients are calculated using the expressions and MC simulations. The results demonstrate clearly a drastic change of the behavior of all diffusion coefficients on the reconstructed surface.
Surface diffusion anomaly near a substrate phase transition: H on W(100).
Using a linear optical diffraction method, we have experimentally studied the long predicted diffusion anomalous behavior for H/W(100) near the reconstructive phase transition of the W(100) substrate. This anomaly manifests itself in the form of a strong dip in the diffusion coefficient D at the transition temperature T(C). We interpret the strong reduction of D as a result of the diverging friction damping near the transition. The finite dip in D instead of a vanishing D at T(C) also demonstrates the importance of the non-Markovian (memory) deviation from the simple instantaneous damping picture.
The effect of adsorbate‐induced surface reconstruction on the apparent Arrhenius parameters for desorption
The effect of adsorbate‐induced surface reconstruction on the apparent preexponential factor and activation energy for desorption is analyzed and discussed. The reconstruction is assumed to be a continuous order–disorder phase transition. The adsorbate‐induced changes in the surface are shown to result in a rather strong (of the order of 102) coverage dependence of the preexponential factor for desorption. The direction of the variation is in accordance with the compensation effect (the preexponential factor and the activation energy decrease with increasing coverage).