Antagonistic model of random sequential adsorption of two-species discorectangles

An antagonistic random sequential adsorption (RSA) model is investigated to describe competitive adsorption on an adsorbent surface by particles of two types, a and b. The degree of competition is characterized by the probability p_{a}(p_{b}=1-p_{a}) that an arriving particle is of type a. Particles of both types are modeled as discorectangles with aspect ratio ɛ=l/d, where l and d denote the particle length and thickness, respectively. Each particle is surrounded by a shell of thickness δ, which induces repulsive interactions between particles of opposite types. This repulsion leads to the spontaneous formation of clusters consisting of particles of a single type, separated from clusters of the opposite type by cavities of thickness approximately 2δ. The mechanisms governing the formation of the adsorption layer and the resulting jamming coverage are analyzed. In addition, the dependence of the shell percolation threshold, δ_{c}, on the probability p_{a} is examined for different values of the shell thickness δ and the aspect ratio ɛ.