Non-Rice-Ramsperger-Kassel-Marcus dynamics and the statistics of reaction rates in chaotic systems

Recrossings of the transition state are normally thought of as modifying the dynamical prefactor (transmission coefficient) which corrects the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. Here, a semiclassical path analysis is used to show that recurrences to parts of phase space from which reactive transitions can occur also lead to fluctuations of the reaction rate about its microcanonical average. This result leads to a simple formula for the power spectrum of the rates.