MOLECULAR-DYNAMICS SIMULATIONS OF PHASE-SEPARATION IN CHEMICALLY REACTIVE BINARY-MIXTURES

A molecular dynamics system of a two dimensional immiscible binary mix ture with a first order chemical reaction that changes a particle from one of the species to the other, is set up, in close analogy to the M onte Carlo investigation of a similar system on a square lattice by S. Glotzer et al. [Phys. Rev. Lett. 72, 4110 (1994)]. In contrast to the ir investigation we do not find any labyrinthlike domain formation at the steady states and no direct equality between the way in that the s ystem scales with respect to reaction rate and growth exponent in the absence of a chemical reaction. The differences are explained by the f act that a stochastic model misses the hydrodynamic modes that are mai nly responsible for the phase separation in this system and that the d iscrete lattice imposes an external field on the domains that order th e steady-state domains in a labyrinthlike structure.