Rice–Ramsperger–Kassel–Marcus (RRKM) theory

https://doi.org/10.1351/goldbook.R05391
An improved form of @[email protected] in which account is taken of the way in which the various [email protected]@ vibrations and rotations contribute to reaction, and allowance is made for the zero-point energies. In this theory the energy \(\varepsilon^{\text{*}}\) in an energized molecule is classified as either active, \(\varepsilon^{\text{*active}}\), or inactive, \(\varepsilon^{\text{*inactive}}\). The rate depends upon \(\frac{P(\varepsilon^{\text{*active}})}{N(\varepsilon^{\text{*}})}\), where \(N(\varepsilon^{\text{*}})\) is the density of states having energy between \(\varepsilon^{\text{*}}\) and \(\varepsilon^{\text{*}}+\text{d}\varepsilon^{\text{*}}\), and \(P(\varepsilon^{\text{*active}})\) is the sum of the active quantum states of the @[email protected] This extension of RRK theory brings it in line with @[email protected]
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 186 [Terms] [Paper]