SEPARATION OF TIME SCALES IN SPECIES CONVERSION BY DIFFUSION-CONTROLLED REACTIONS IN A BINARY SUSPENSION OF SPHERES

Transient diffusion-controlled reactions in a binary suspension of equ al-sized spheres are studied in a region of the equilibrium phase diag ram, where a separation of time scales occurs. In Ising model language , the suspension consists of hard spheres with an internal classical s pin taking two values, with a square well Ising interaction and with a magnetic field present. Transitions can occur whenever a pair of sphe res approaches within the range of the Ising interaction. A separation of time scales is observed near the ferromagnetic phase transition. T his allows a simplified phenomenological description of the relaxation of magnetization. (C) 1997 American Institute of Physics.