Diffusion-limited reactions on disordered surfaces with continuous distributions of binding energies

We study the steady state of a stochastic particle system on a two-dimensional lattice, with particle influx, diffusion and desorption, and the formation of a dimer when particles meet. Surface processes are thermally activated, with (quenched) binding energies drawn from a continuous distribution. We show that sites in this model provide either coverage or mobility, depending on their energy. We use this to analytically map the system to an effective binary model in a temperature-dependent way. The behavior of the effective model is well understood and accurately describes key quantities of the system: compared with the case for discrete distributions, the temperature window of efficient reaction is broadened, and the efficiency decays more slowly at its ends. The mapping also explains in what parameter regimes the system exhibits realization dependence.