Rice-Ramsperger-Kassel-Marcus expression

Theoretical Expressions. The Rice-Ramsperger-Kassel-Marcus (RRKM14) theory of unimolecular reactions employs a quantum statis-... 

The commonly used simplification to this approach is to use the Rice-Ramsperger-Kassel-Marcus (RRf ) expression, which invokes transition state theory (TST) to evaluate the flux through the transition state, leading to... 

This is the Rice-Ramsperger-Kassel-Marcus (RRKM) expression of the reaction rate constant at energy E [127]. For total energies E below the potential energy of the transitions state, i.e., for E < F(/ts), k E) vanishes. The canonical and the microcanonical rate constants are related by a Laplace transform, ... 

Rabinovitch et al. (85) studied the reaction of H atoms with trans-ethylene-d2 as a function of ethylene pressure in the temperature range — 78 to 160°C. They were able to account for all secondary reactions of the hot ethyl radicals and to determine the rates of their decomposition (relative to stablization). Simultaneously they calculated the theoretical rates on the basis of the Rice-Ramsperger-Kassel theory of uni-molecular reactions, using expressions derived by Marcus (71), and found a reasonable agreement with the experimental values. Similar satisfactory agreements had been found previously by Rabinovitch and Die-sen (84) for hot sec-butyl radicals. Extensive studies of hot radicals produced by H or D atom additions to various olefins have been carried... 

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