Symmetry Numbers and Reaction Rates

Abstract

It is shown here that absolute rate theory, in its use of symmetry numbers in the rotational partition functions, does not provide an infallible recipe for considering the possibility of multiple reaction paths. The conditions under which this recipe must fail are considered; and hence, in absolute rate theory calculations a correction factor must be included beyond that provided by the symmetry numbers. A general recipe is given for calculating the reaction path multiplicity; a direct count of all possibilities will, of course, always provide the correct answer.