Ordering models vibrational energy effects

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. 

The present perturbative beatment is carried out in the framework of the minimal model we defined above. All effects that do not cincially influence the vibronic and fine (spin-orbit) stracture of spectra are neglected. The kinetic energy operator for infinitesimal vibrations [Eq. (49)] is employed and the bending potential curves are represented by the lowest order (quadratic) polynomial expansions in the bending coordinates. The spin-orbit operator is taken in the phenomenological form [Eq. (16)]. We employ as basis functions... 

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