Other applications of transition-state theory

The application of transition-state theory to unimolecular reactions is very straightforward. With the subscript 1 identifying the reactant, equation (70) reduces to 

The activated complex should differ from the reactant primarily in having one vibrational bond broken. If qy denotes the partition function for this vibrational mode, then equation (76) becomes, approximately. 

Transition-state theory can be developed for reactions occurring on surfaces by a procedure paralleling that given in Section B.3,4 [2]. The only modifications required are that volume concentrations must be replaced by surface concentrations and that a factor representing the concentration (number per unit surface area) of active surface sites at which the reaction may occur must be introduced. The viewpoint of transition-state theory can also easily be extended to include rate predictions for vaporization (for example, [54]) and for other heterogeneous processes involving phase changes. 

There are more-recent developments in reaction-rate theory that yield a deeper understanding of certain reactions than can be obtained with 

The importance of electronically excited states in reaction kinetics is well established [14]. Electronic excitation leads to qualitative as well as to quantitative modifications in the preceding theories, especially in connection with the intersection of the potential-energy surfaces corresponding to different electronic states. Structures of electronically excited activated complexes have been studied (for example, [55]) and have been used in postulating kinetic mechanisms for the production of nonequilibrium excited species that have been observed (for example, [56]) in hydrogen-oxygen flames. 

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