Fragments Distribution Frequency

The frequency with which the transition state is transformed into products, iT, can be thought of as a typical unimolecular rate constant no barrier is associated with this step. Various points of view have been used to calculate this frequency, and all rely on the assumption that the internal motions of the transition state are governed by thermally equilibrated motions. Thus, the motion along the reaction coordinate is treated as thermal translational motion between the product fragments (or as a vibrational motion along an unstable potential). Statistical theories (such as those used to derive the Maxwell-Boltzmann distribution of velocities) lead to the expression ... 

Recent work (161) with a tunable VUV flash lamp has shown that the CN(A2II) can be detected directly using the LIF technique. Thus one is able, in principle, to determine the vibrational and rotational population of each of the fragments (CN(X2E), (A2n)). The tunable UV flash lamp allows one to measure these quantum state distributions as a function of the vibrational frequency of the upper electronic state. The results from these studies thus far are summarized in Table 8. 

Fig. 14.11 Length distributions of the fragments outside the proteasome. From left to right the efflux rate e increases e = (0.1, 1, 10). Each distribution has been taken at the time 170 (a), 86 (b), 76 (c) when 20 % of substrate degraded. The vertical on each plot is the log frequency (from 0 to 0.25). The influx rate a = 0.01. Note that the distributions are insensitive to the variation in the influx rate a [27],...

Figure 6 presents the frequency distribution of enamine fragments (number of entries considered in this chapter) published over the years in the period 1969-1991. 

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