The primary process in the photolysis of hexafluoroacetone vapour V. Mechanistic considerations

Abstract

Data presented in the previous parts of this series are discussed in terms of the mechanism adopted for the primary process and it is noted that the data follow the general trends predicted by that mechanism. Five independent tests applied to the data indicate that the vibrational relaxation in the S 1 state occurs by a cascade of weak collisions; although the number of stages involved cannot be determined with precision, it is unlikely to exceed five. Rate constants are evaluated from the data for reactions (4) to (9). A reasonably reliable value of E 8 = 16 kcal/mole was obtained. The value of A s suggests that the decomposition from the trip let occurs along a single potential surface. This hypothesis is developed to suggest that molecules which decompose from the singlet state possibly do so via an unbounded region of the triplet surface.