Accession Number : AD0787813

Title :   Nucleation in Systems with Multiple Stationary States.

Descriptive Note : Technical rept.,

Corporate Author : PURDUE UNIV LAFAYETTE IND PROJECT SQUID HEADQUARTERS

Personal Author(s) : Nitzan,A. ; Ortoleva,P. ; Ross,J.

Report Date : SEP 1974

Pagination or Media Count : 38

Abstract : The authors consider a reaction diffusion system, far from equilibrium, which has multiple stationary states (phases) for given ranges of external constraints. If two stable phases are put in contact, then in general one phase annihilates the other and in that process there occurs a single front propagation (soliton). The macroscopic dynamics of the front structure and velocity for two model systems are investigated analytically and numerically, and for general reaction-diffusion systems by a suitable perturbation method. The vanishing of the soliton velocity establishes the analogue of the Maxwell construction used in equilibrium thermodynamics. The problem of nucleation of one phase imbedded in another is studied by a stochastic theory. It is shown that if the reaction dynamics is derived from a generalized potential function than the macroscopic steady states are exterma of the probability distribution. This result is used to obtain an expression for the critical radius of a nucleating phase and confirm the prediction of the stochastic theory by numerical solution of the deterministic macroscopic kinetics for a model system. (Modified author abstract)

Descriptors :   *Diffusion, *Nucleation, *Phase studies, *Reaction kinetics, Phase transformations, Stochastic processes

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE