https://doi.org/10.1351/goldbook.T06470
A theory of the rates of , to exist between reactants and activated complexes. According to this theory the where is the is the where , the , the (the are not quite the same, the relationship between them depending on the type of reaction. Also: where , known as the , which is the , and occurring in the former three equations are not ordinary thermodynamic quantities, since one degree of freedom in the
elementary reactions
which assumes a special type of equilibrium, having an equilibrium constant
rate constant
is given by: Boltzmann constant
and Planck constant
. The rate constant
can also be expressed as: entropy of activation
, is the standard molar change of entropy
when the activated complex
is formed from reactants and enthalpy of activation
, is the corresponding standard molar change of enthalpy
. The quantities energy of activation
) and Gibbs energy of activation
, is the standard molar Gibbs energy change for the conversion of reactants into activated complex
. A plot of standard molar Gibbs energy against a reaction coordinate
is known as a Gibbs-energy profile
; such plots, unlike potential-energy profiles
, are temperature-dependent. In principle the equations above must be multiplied by a transmission coefficient
, probability
that an activated complex
forms a particular set of products rather than reverting to reactants or forming alternative products. It is to be emphasized that activated complex
is ignored. Transition-state theory has also been known as absolute rate theory, and as activated-complex theory, but these terms are no longer recommended.