Control parameters microscopic reversibility

The most common initiation or homolysis reaction is the breaking of a covalent C-C bond with the formation of two radicals. This initiation process is highly sensitive to the stability of the formed radicals. Its activation energy is equal to the bond dissociation enthalpy because the reverse, radical-radical recombination reaction is so exothermic that it does not require activation energy. C-C bonds are usually weaker than the C-H bonds. Thus, the initial formation of H radicals can be ignored. The total radical concentration in the reacting system is controlled both by these radical initiation reactions and by the termination or radical recombination reactions. In accordance with Benson (1960), the rate constant expressions of these unimolecular decompositions are calculated from the reverse reaction, the recombination of two radical species to form the stable parent compound, and microscopic reversibility (Curran et al., 1998). The reference kinetic parameters for the unimolecular decomposition reactions of K-alkanes for each single fission of a C-C bond between secondary... 

To reify this very important point further, let us consider the two ratchet models shown in Fig. 9. At first glance it would seem that the ratchet in Fig. 9a is designed for transport to the right and that in Fig. 9b is designed for transport to the left. Despite appearances, however, both ratchets operate as Brownian information motors [9]. When the rate constants are assigned consistent with microscopic reversibility, the intrinsic directionality of each ratchet is controlled by the parameter... 

Consider a system initially at state A and in interaction with an environment at temperature T = l/ where the Boltzmann constant is unity. The system depends on jc representing all the dynamical, uncontrolled degrees of freedom and some external, controlled, and time-dependent parameter A. The dynamics of the system satisfy the microscopic reversibility condition ... 

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