A model reaction coordinate potential energy curve for a fluxioral molecule 
Theory of Intramolecular and Unimolecular Dynamics
RiceRamspergerKasselMarcus (RRKM) theory is
widely used in interpreting the rates of unimolecular reactions. The
theory assumes that intramolecular vibrational energy redistribution (IVR) occurs on a timescale much faster than the
unimolecular reaction. The X ^{}CH_{3}Y
S_{N}2 complexes and trimethylene dissociation are two
unimolecular systems where the rapid IVR
assumption of RRKM theory is not valid. There is
much interest in developing theoretical models to represent the
intramolecular and unimolecular dynamics of such systenms.
