Bimolecular reaction rate constant

Bimolecular Reaction Rate Constant for the End Functional Groups During Network Formation... 

In summary, the QRRK theory result for the observed bimolecular reaction rate constant fcbimol was given by Eq. 10.198 as... 

This is known as the Stern-Volmer equation, where ksv is the bimolecular reaction rate constant (in units of M-1 s-1). From an experimental viewpoint, the plot of k0bS as a function of [Q] is a straight line, of slope ksv the lifetime decreases as a function of [Q], The global luminescence intensity of M as a function of [Q] is equal to ... 

In contrast, when An 0 one finds considerable disagreement in the literature concerning relative gas and liquid equilibrium (and rate) constants, even in the absence of solvation effects. Depending on the particular theoretical treatment, bimolecular reaction rate constants have been estimated to be somewhere between 2 and 100 times faster in solution than in the gas phase (6). However, the very limited experimental data available indicate that there is little, if any, systematic difference between bimolecular rate constants in the two phases (6d). 

The rate constants presented in Table 2 suggest that the N03 radical reactions with the gas-phase PCBs and PCDFs have upper limits to the rate constants for any reaction of fcabs < 10-15 cm3 molecule-1 s-1 (N02 concentrations in the troposphere are sufficiently low that the contribution of any N02-dependent reaction is encompassed within the upper limit to the bimolecular reaction rate constant fcabs). While dibenzo-p-dioxin and 1-chlorodibenzo-p-dioxin react with the N03 radical by the N02-dependent mechanism shown in Scheme 1 and equation (13), the N02 concentrations in the troposphere are sufficiently low that the effective bimolecular rate constants, fca(fcc[N02] + fcd[02])/fcb, are below the upper limits to the rate constants fcabs. 

In equation (1) K y is referred to as the Stern-Volmer constant Equation (1) applies when a quencher inhibits either a photochemical reaction or a photophysical process by a single reaction. <1>° and M° are the quantum yield and emission intensity (radiant exitance), respectively, in the absence of the quencher Q, while <1> and M are the same quantities in the presence of the different concentrations of Q. In the case of dynamic quenching the constant K y is the product of the true quenching constant kq and the excited state lifetime, t°, in the absence of quencher, kq is the bimolecular reaction rate constant for the elementary reaction of the excited state with the particular quencher Q. Equation (1) can therefore be replaced by the expression (2)... 

Solvent Viscosity Dependence of Bimolecular Reaction Rate Constant of the Excited 9-Cyanoanthracene Quenched by 1,3-Cyclohexadiene... 

A computer simulation approach has been derived that allows detailed bimolecular reaction rate constant calculations in the presence of these and other complicating factors. In this approach, diffusional trajectories of reactants are computed by a Brownian dynamics procedure the rate constant is then obtained by a formal branching anaylsis that corrects for the truncation of certain long trajectories. The calculations also provide mechanistic information, e.g., on the steering of reactants into favorable configurations by electrostatic fields. The application of this approach to simple models of enzyme-substrate systems is described. 

Fig. 33. Comparison of the predicted bimolecular reaction rate constant for CIO + CIO -> CI2 + O2 with the experimental values. Solid line is the predicted total value coupling Schemes 1 and 2 dotted line is the contribution from Scheme 2. Symbols are the experimental values as described in Ref 119.

FIGURE 23 Experimentally determined bimolecular reaction rate constants for H + CO2 reaction photoinitiated in HI CO2 van der Waals complexes. Solid line denotes calculated RRKM decomposition rate for HOCO reaction intermediates. (From Ionov, S. I., Brucker, G. A., Jaques, C., Valachovic, L., and Wittig, C. (1992). J. Chem. Phys. 97, 9486-9489.)... 

Usually, due to diffusion hmitations, the bimolecular reaction rate constant 2 does not exceed 10 dm mol s and then the ratio is of the order... 

NAD (P)+-dependent enzymes, electrically contacted with electrode surfaces, can provide efhcient bioelectrocatalysis for the NAD(P)H oxidation. For example, diaphorase (DI) was applied to oxidize NADFl, using a variety of quinone compounds, several kinds of flavins, or viologens as mediators between the enzyme and electrode [217, 218]. The bimolecular reaction rate constants between the enzyme and mediators whose redox potentials are more positive than -0.28 V at pH 8.5 can be as high as 10 s , suggesting that the reac-... 

Experimentally, in most of the cases bimolecular reaction rate constants are known to be expressed by... 

Recent measurements of the reaction rate constants following the above scheme have been conducted by Golden et al. (1998), McCabe et al. (2001), etc., and the data including these studies have been compiled by the NASA/JPL evaluation No. 17 (Sander et al. 2011). At the low-pressure limit, the reaction proceeds via the path (5.26), and the bimolecular reaction rate constant is recommended as. 

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