Theory of rate processes

A quantitative theory of rate processes has been developed on the assumption that the activated state has a characteristic enthalpy, entropy and free energy the concentration of activated molecules may thus be calculated using statistical mechanical methods. Whilst the theory gives a very plausible treatment of very many rate processes, it suffers from the difficulty of calculating the thermodynamic properties of the transition state. 

S. Glasstone, K. J. Laidler, and H. Eyring, The Theory of Rate Processes, McGraw-Hill, New York, 1941. 

Giasstone S, Laidier K J and Eyring Fi 1941 The Theory of Rate Processes (New York McGraw-Fiiii)... 

Glasstone, S. Laidler, K.J. Eyring, H. The Theory of Rate Processes McGraw-Hill New York, 1948 pp 472-3. 

According to the theory of rate processes (Eyring et al., 1941), reaction rate constants are determined by the expression... 

B Fain, Theory of Rate Processes in Condensed Media, Sprmger-Verlag, Berlin 1980... 

Glasstone, S., Laidler, K. J., and Eyring, H. (1941), Theory of Rate Processes, McGraw Hill, New York. Langevin, M. P. (1905), J. Chim. Phys. 5, 245. English translation in McDaniel, E. W. (1964), Collision Phenomena in Ionized Gases, app. 1, Wiley, New York. 

In conventional theories of rate processes, the temperature T is usually involved. The involvement of T implicitly assumes that vibrational relaxation is much faster than the process under consideration so that vibrational equilibrium is established before the system undergoes the rate process. For example, let us consider the photoinduced ET (see Fig. 5). From Fig. 5 we can see that for the case in which vibrational relaxation is much faster than the ET, vibrational equilibrium is established before the rate process takes place in this case the ET rate is independent of the excitation wavelength and a thermal average ET constant can be used. On the other hand, for the case in which the ET is much faster than vibrational relaxation, the ET takes place from the pumped vibronic level (or levels) and thus the ET rate depends on the excitation wavelength and often quantum beat will be observed. 

A chemical reaction is then described as a two-fold process. The fundamental one is the quantum mechanical interconverting process among the states, the second process is the interrelated population of the interconverting state and the relaxation process leading forward to products or backwards to reactants for a given step. These latter determine the rate at which one will measure the products. The standard quantum mechanical scattering theory of rate processes melds both aspects in one [21, 159-165], A qualitative fine tuned analysis of the chemical mechanisms enforces a disjointed view (for further analysis see below). 

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