LAUSR

We present the thermochemical model in the tristable regime which is characterized by three distinct attractors: two stationary states and a limit cycle. Transitions between the attractors are studied on the basis of the stochastic dynamics at the mesoscopic level, in which internal fluctuations are described by means of the master equation. Simulations of the stochastic dynamics follow the master equation, which has the specific form due to the necessary description of a continuous spectrum of temperature changes related to the exchange of energy with a thermostat. The mean first passage times are calculated for transitions from the limit cycle to each stable steady state. The effect of competition between the states is demonstrated: the duration of the passage can be strongly increased if the system during the transition to one state is also visiting the second competitive one. The variation of the passage times is studied for systems with different reaction heat, and the obtained dependence is explained by the location of the attractors and repellers in the phase space of system temperature and composition. The proportion between the mean passage times for the two states can be related to their relative strength of attraction.