Random-walk analysis, surface diffusion

Surface diffusion may be treated by a random-walk analysis. We assume that the molecular motion is completely random and that the jumps from site to site are of equal length, which is equal to the nearest-neighbor distance d. With these assumptions, the preexponential factor for diffusion is (23). 

Measurements of surface diffusion can be correlated in terms of random walk, surface mobility, and surface diffusion coefficients. Correlations in terms of surface diffusion coefficients are most similar to the type of analysis used in this book. The surface diffusion coefficient is defined with the equation... 

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