LONG-TIME TAILS IN CANONICAL ENSEMBLE UNIMOLECULAR DECAY

Decay of a canonical ensemble of noninteracting metastable reactant species is investigated with respect to the effects of nonergodicity due to energy and angular momentum conservation. Cases of energy conservation alone, and both energy and angular momentum conservation, are considered separately in analytic treatments. The result is the prediction of algebraic asymptotic decay of the form, O[t-1/(n-1)]. In the case of E and J conservation, n=3N-6, where N is the number of reactant atoms. Otherwise, n is the number of reactant degrees of freedom. Numerical computations of T-shaped Ar3 inversion exhibit O(1/t) long time tails in population decays, in agreement with theory.