FIELD AND DIMENSIONALITY EFFECTS IN TRAPPING REACTION-KINETICS

We analyze the main properties of a diffusion-controlled reaction of t he type A + T --> T in the presence of a field that affects the mobile particles A but not the fixed traps T. For one-dimensional systems a steady state is reached exponentially fast if the field points towards the trap. If the system dimension is two or higher, a steady state is always reached. In this steady state there is an anisotropically pert urbed region whose relative size decreases as the system dimension is increased. This perturbed region always contains a depletion zone down stream and, if the held is sufficiently strong, we observe an excess o f diffusing reactants upstream from an imperfect trap. We present form ulas to calculate the steady-state concentration, the nearest-neighbor distribution, the reaction rate, and the diffusion-controlled growth rate of a droplet.