Nonuniversality and Breakdown of Scaling in a Two-Component Coagulation Model

We investigate the kinetics of a coagulation process involving two distinct bifunctional monomeric species $A$ and $B$ (which can be ascribed a positive and negative "charge," respectively) with bonding allowed only between $A$ and $B$. When the rates for charged-charged, neutral-neutral, and neutral-charged reactions are all distinct, we find, from the solution to the mean-field rate equations, that (i) the kinetic exponents are nonuniversal and (ii) a scaling description of the clustersize distribution fails. Similarly intriguing results are also found for the kinetic behavior below the upper critical dimension.