Troe correction factors

This estimate is then improved by the inclusion of a series of correction factors, which were derived and developed by Troe [67,68]. 

The strong collision correction factor Fsc is a function of two further parameters that arise in Kassel theory (see Section 3). These are the number of effective oscillators, S, and B = Eg/kT, a measure of the relative magnitudes of the threshold energy and thermal energy. Troe used an energy criterion to obtain the number of effective oscillators. 

It is obvious that anharmonic corrections are often not small for molecules with a single potential minimum and attempts have been made to represent them by analytic expressions. Following work by Harhoff, Troe suggested the correction factor ... 

Troe gives an expression for kQ in terms of factors such as the harmonic density of states, the Lennard-Jones collision frequency, the vibrational partition function, and the critical energy, Eq, as well as terms to account for anharmonicity corrections, the energy dependence of the density of states, and rotational effects. We use equation (1) of reference 76 to estimate kQ. Expressions to evaluate each of the factors in that equation are summarized in reference 75. For the purpose of this discussion, 6c =1 unimolecular dis-... 

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