Relative ’’dynamic stabilities’’ of stationary states in pumped chemical systems

When a chemical system is pumped with a continuous flux of radiant energy or high energy chemicals, it usually relaxes to a stationary state that remains invariant as long as the flux remains constant. Although the stationary state composition is often a unique function of pumping conditions, some systems can exhibit two or more stationary states within a considerable range of pumping rates. It two different stationary states can be created by identical pumping conditions, one test of relative ’’dynamic stability’’ is to determine which state becomes dominant when they are mixed. Applicability of this criterion has been examined by model calculations on reactions in a continuously stirred tank reactor (CSTR). If the chemical process involves a single reactant and product, the pumping rate generating ’’dynamic equistability’’ is that at which probabilities are equal as to which of two different identically pumped systems will become dominant as a result of mixing. An argument based on the Gibbs free energy function provides a method for treating mixing of more complicated pumped systems. A purely kinetic treatment of such systems is reserved for a later manuscript. Comparison of different computational procedues indicates it is not possible to define relative dynamic stabilities of stationary states in identically pumped systems even though relative thermodynamic stabilities can be unequivocally assigned to unpumped systems.