Reversible diffusion-controlled reactions in a disordered system of staticspherical catalysts

The effective frequency-dependent rate coefficient for conversion of partic les diffusing in a disordered system of static spherical catalysts is calcu lated for low density of catalysts by the method of multiple scattering the ory. The rate coefficient follows from a Foldy-Lax type formula. The cataly sts are assumed uniform, but different energies, conversion rates, and diff usion coefficients are allowed inside and outside the catalysts. The freque ncy-dependent rate coefficient is characterized by its steady-state value a nd by a spectrum of relaxation rates. The coefficient displays a wide varie ty of behavior as a function of the parameters of the model. (C) 1999 Ameri can Institute of Physics. [S0021-9606(99)50433-9].