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Rate kernel structure

Since the complications due to solvent structure have already been discussed, the remainder of this chapter is mainly devoted to a discussion of the complications introduced into the theory of reaction rates when the collision of solvent molecules does not lead to a complete loss of memory of the molecules about their former velocity. Nevertheless, while such effects are undoubtedly important over some time scale, the differences noted by Kapral and co-workers [37, 285, 286] between the rate kernel for reaction estimated from the diffusion and reaction Green s function and their extended analysis were rather small over times of 10 ps or more (see Chap. 8, Sect. 3.3 and Fig. 40). At this stage, it is a moot point whether the correlation of solvent velocity before collision with that after collision has a significant and experimentally measurable effect on the rate of reaction. The time scale of the loss of velocity correlation is typically less than 1 ps, while even rapid recombination of radicals formed in close proximity to each other occurs over times of 10 ps or more (see Chap. 6, Sect. 3.3). [Pg.320]

On Laplace inversion and then inserting the rate kernel into the Noyes expression for the rate coefficient [eqn. (191)], the rate coefficient is seen to be exactly that of the Collins and Kimball [4] analysis [eqn. (25)]. It is a considerable achievement. What is apparent is the relative ease of incorporating the dynamics of the hard sphere motion. The competitive effect comes through naturally and only the detailed static structure of the solvent is more difficult to incorporate. Using the more sophisticated Gaussian approximation to the reactant propagators, eqn. (304), Pagistas and Kapral calculated the rate kernel for the reversible reaction [37]. These have already been shown in Fig. 40 (p. 219) and are discussed in the next section. [Pg.353]

The results given above are the correlation function expressions for the rate coefficient, which we wished to obtain. The last line also serves to define the quantity k z the rate kernel. As noted earlier, this quantity is central to discussion of reaction rate theory. Here and in the sections that follow, we attempt to elucidate its structure. [Pg.91]

If the reaction can not be modeled by an impulsive collision event, as for atomic recombination or some isomerization reactions, then is zero by time reversal symmetry as discussed earlier. Nevertheless, the structure of the rate kernel has the same qualitative structure as described above. To... [Pg.104]

If we wish to examine only the structure of the rate kernel, we know that it is sufficient to study the decay of fluctuations about equilibrium. If we let... [Pg.109]

Before closing this section, we should remark that although this analysis of velocity relaxation effects has focused on a simple collision model, we expect that the detailed structure of the rate kernel for short times will depend on the precise form of the chemical interactions in the system under consideration. It is clear, however, that a number of fundamental questions need to be answered before more specific calculations can be undertaken form the kinetic theory point of view. [Pg.149]

The global structure of IET formalism is similar to that of DET. The integral kinetic equations substitute for their differential analogs. The kernels of these equations are defined by the transfer rates and pair distribution functions. The auxiliary equations for these functions are also similar but not identical to those in DET. In the next section we will see that the integral theory may sometimes be reduced to the differential one, albeit under rigid conditions and with some losses. [Pg.158]

The instability of rice bran has long been associated with lipase activity (35). As long as the kernel is intact, lipase is physically isolated from the lipids (29). Even dehulling disturbs the surface structure allowiug lipase and oil to mix. Oil in intact bran contains 2—4-% free fatty acids (2). Once bran is milled from the kernel, a rapid increase in the FFA occurs, lu high huuiidity storage, the rate of hydrolysis is 5-10% per day and about 70% in a month as shown earlier. The objectives of rice bran stabilization are as follows ... [Pg.1111]

Tables 8.14 and 8.15 summarize the misclassification rates for the test sets. Table 8.14 contains results for variable selection using CART. Obviously, classification by LDA has better predictive ability than classification by CT for these descriptor sets. Looking at the arithmetic meem or medieui over all 77 structural properties, SVMs with radial kernel exhibit the lowest misclassification rates. Tables 8.14 and 8.15 summarize the misclassification rates for the test sets. Table 8.14 contains results for variable selection using CART. Obviously, classification by LDA has better predictive ability than classification by CT for these descriptor sets. Looking at the arithmetic meem or medieui over all 77 structural properties, SVMs with radial kernel exhibit the lowest misclassification rates.
Table 8.16. Misclassification rates of MS classifiers (SVM with radial kernel) for 77 structural properties. Table 8.16. Misclassification rates of MS classifiers (SVM with radial kernel) for 77 structural properties.
The effects of liquid content, bed depth, and drum rotation rate on the coalescence behavior can be quantified through the development of new kernel models with the structure described by Eqs 5.18 and 5.19. The simulation results are qualitatively consistent with industrial experience in large-scale... [Pg.590]

Lather volume depends upon the amount and the type of soap dissolved in the soap liquor during lathering. The mobility of the soap molecules, in addition to their surface properties, contributes to foaming. It is therefore possible that the soaps with very short chains (sodium caprylate and sodium caprate) may have an additional lather benefit. However, the proposed benefit should be restricted to low wash temperatures. The source of the short chain soaps is the coconut or palm kernel oil component of the fat charge. The amount of soap in solution in the wash liquor increases as the level of soluble soap in the bar increases. However, because the lather depends on the very short transient hydration period, it is the amount of soap which goes into solution over this period that is important. This amount also increases as the rates of dissolution of the solid soluble phases of the bar structure increase. [Pg.57]

By using SVC with linear kernel function, 100% of separation of the chlorides with perovskite structure and the chlorides with face-shared structures can be achieved. And the sample point of the borderline case, CsCdCb, is located close to the optimal hyperplane of classification. In leave-one-out (LOO) cross-validation test, the rate of correctness of prediction is 91%. [Pg.161]

The 100 orientation structure-forming region and mixed orientation structure-forming region is not linearly separable. But using Gaussian kernel the separation is good and the rate of correctness of prediction in... [Pg.180]


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See also in sourсe #XX -- [ Pg.101 , Pg.102 , Pg.103 , Pg.104 ]




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