Computer simulation of Eley-Rideal reactions over rough surface

The effect of surface roughness on an Eley-Rideal reaction mechanism is studied. The rough surfaces are generated over a 2-dimensional square lattice using the random deposition model. In an Eley-Rideal reaction mechanism, a reacting particle approaches from the bulk and reacts with an active site upon collision with it. Three different rough surfaces are considered for the study. Multifractal scaling analysis is performed where the complex distribution of reaction probabilities is analyzed. Two cases of reactions are considered. 1) The reacting particle reacts at its first contact to the surface and 2) the reacting particle diffuses till it finds the lowest-height position and reacts. The results obtained from the above two cases are compared. Significant differences between tau(q) and f(alpha) multifractal spectra for these two cases are found. The larger deviation from linearity in the tau(q) curves for the latter than the former gives wider f((alpha) spectra, indicating greater heterogeneity in the reaction probability distribution. Dynamic scaling theory is also applied on the Eley-Rideal reaction mechanism over the surface with different surface roughnesses to obtain the two scaling parameters alpha(d) and beta(d). The values of alpha(d) and beta(d) are found to be negative.