SPATIAL-ORGANIZATION IN 2-SPECIES ANNIHILATION

The spatial structure of reactants in the two-species annihilation reaction A + B --> 0 is described. In one dimension, we investigate the distribution of domain sizes and the distributions of nearest-neighbor distances between particles of the same and of opposite species. The latter two quantities are characterized by a new length scale which is intermediate to the domain size t1/2 and the typical interparticle spacing t1/4. A scaling argument suggests that the typical distance between particles of opposite species, or equivalently the gaps between domains, grows as t(zeta), with zeta = 3/8 and 1/3, respectively, in spatial dimension d = 1 and 2. The average density profile of a single domain is spatially non-uniform, with the density decaying to zero linearly as the domain edge is approached. This behavior permits a determination of the distribution of nearest-neighbor distances of same-species reactants. The corresponding moments of this distribution exhibit multiscaling which involves geometric averages of different powers of the domain size and the interparticle spacing.