High Concentration Limit of Unimolecular Reaction Kinetics

Abstract

A general sum-over-states form of the Lindemann theory of unimolecular reactions is analyzed with respect to properties in the high concentration region, and results are compared with similar deductions found in the low concentration region. In a general form the theory can set a limit on the low concentration rate constant from data taken in the high concentration region alone, and it can set a limit on the high concentration rate constant from data taken in the low concentration region alone. If there are data at both the low and high concentration regions, one can compute two dimensionless parameters which are useful in interpreting kinetic data. In particular, these parameters may be used to select the number of oscillators and their frequency in the Rice-Ramsperger-Kassel form of the theory. These methods are applied to nitrogen pentoxide and nitrous oxide.