Heterogeneous Reactions Over Fractal Surfaces: A Multifractal Scaling Analysis

Ž . Monte Carlo simulations of Eley]Rideal ER mechanisms with fixed and varying Ž . sticking probabilities, p, as well as a three-step catalytic reaction TCR over fractal surfaces were performed to examine the morphological effect on the above-mentioned reactions. The effect of decay and enhancing profiles on the reaction probability Ž . distribution RPD for the ER reaction as well as effects of a varying probability of Ž . reaction steps on the normalized selectivity distribution NSD for the three-step reaction were then analyzed by multifractal scaling techniques. For ER with a fixed sticking probability, a small p value tends to yield homogeneous RPD. For ER with a varying sticking probability, the RPD is revealed to be spatially uniform at fast decay and rather concentrated at a faster enhancing rate. For the three-step reaction, a large dimerizationrisomerization ratio increases the position distinction among active sites as the adsorption probability equals 1. At a small adsorption probability, the dimerizationrisomerization ratio causes no effect on the NSD. Heterogeneity of surfaces as reflected in the multifractal analysis will also be discussed. Q 1997 John Wiley & Sons,