RRKM theory strong coupling

RRKM theory assumes the mieroeanonieal ensemble exists at t = 0 and is maintained during the unimolecular decomposition. For the latter to occur, repopulation of the decomposing states results from rapid intramolecular vibrational energy redistribution (IVR). The states are strongly coupled. 

If the RRKM assumption of random access is invalid, different models must be formulated in order to obtain an expression for k(e), if (9.31) is to be used. Slater investigated the other extreme model and assumed no vibrational energy transfer between normal modes of a molecule. This approach is too restrictive. Recent work attempts to steer a middle (and more difficult) course.The dynamics of vibrational energy transfer are incorporated in the theory. Effects attributable to vibrational excitation of modes both strongly and weakly coupled to the critical coordinate can then be exhibited. 

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