Time Dependent Fluctuation in a Nonlinear Chemical System

Abstract

By using a stochastic model of a certain autocatalytic chemical system, the characteristic behaviour of fluctuation is analyzed in relation to the distance from equilibrium. A sample process of fluctuation around a stationary state is traced by means of computer simulation. The characteristic behaviour of fluctuation and of the reaction process hidden in fluctuation are investigated by the statistical analysis of this sample process. Following results are obtained: Probability density distribution is Poisson’s at equilibrium. As the value of affinity becomes large, the distribution is deformed from Poisson’s. In the range of frequency high enough, intensity of the frequency spectrum of fluctuation is a constant independent of the value of affinity. The fluctuation processes of each molecule are statistically independent each other at equilibrium. As the value of affinity becomes large, those processes have statistically intimate dependency.