Universal scaling for diffusion-controlled reactions among traps

The determination of the mean survival time τ (i.e., inverse reaction rate) associated with diffusion-controlled reactions among static traps is a problem of long-standing interest, dating back to the classical work of Smoluchkowski. For the broad class of model particulate- and digitized-based models considered here, we find a universal curve for the mean survival time τ for a wide range of porosities. The functional form of this universal scaling relation is motivated by rigorous bounds on τ and is expressible as a simple function of porosity, specific surface, and mean pore size.