Fractal structures for a catalysed reaction on homogeneous and fractal surfaces

The reaction on a catalytic surface of a monomer and a dimer that dissociates is studied by the Monte Carlo method. The surface is represented by a square lattice and two fractals of the kind diffusion limited aggregation (DLA) cluster, and interaction between neighbours is considered. There is a reactive range for a control parameter between two ranges in which the surface is poisoned by one or the other kind of particles. In most cases, the transition between poisoned and reactive states is a second order one. Adsorbed particles exhibit fractal structures, which are not only determined by the fractal structure of the substrate, but also by the fraction of pairs of adjacent sites in the lattice and the interaction between neighbours.