A factor determination

The fit of the LH model to the remaining kinetic data for the nitrile solvents employed only two fitting parameters, the low-frequency promoting mode, ooq, and the solvent reorganization energy, Es. A factor determining the magnitude of... 

An interesting question then arises as to why the dynamics of proton transfer for the benzophenone-i V, /V-dimethylaniline contact radical IP falls within the nonadiabatic regime while that for the napthol photoacids-carboxylic base pairs in water falls in the adiabatic regime given that both systems are intermolecular. For the benzophenone-A, A-dimethylaniline contact radical IP, the presumed structure of the complex is that of a 7t-stacked system that constrains the distance between the two heavy atoms involved in the proton transfer, C and O, to a distance of 3.3A (Scheme 2.10) [20]. Conversely, for the napthol photoacids-carboxylic base pairs no such constraints are imposed so that there can be close approach of the two heavy atoms. The distance associated with the crossover between nonadiabatic and adiabatic proton transfer has yet to be clearly defined and will be system specific. However, from model calculations, distances in excess of 2.5 A appear to lead to the realm of nonadiabatic proton transfer. Thus, a factor determining whether a bimolecular proton-transfer process falls within the adiabatic or nonadiabatic regimes lies in the rate expression Eq. (6) where 4>(R), the distribution function for molecular species with distance, and k(R), the rate constant as a function of distance, determine the mode of transfer. 

Harrison, A.G. Finney, C.D. Sherk, J.A. Factors Determining Relative Ionic Abundances in Competing Fragmentation Reactions. Org. Mass Spectrom. 1971, 5, 1313-1320. 

Figure 11.13 shows a typical DO AS spectrum measured in air after correcting for atmospheric background light and an electronic offset (Stutz and Platt, 1997). Below the spectrum are shown reference spectra for the gases that contribute to the atmospheric spectrum, scaled by the a, factors determined using Eq. (H). In this case, O, N02, SOz, and HCHO all contribute, leaving a residual spectrum with a peak-to-peak absorbance of 6 X 10 4. 

The nature of the cation (K+ or Na+) in hydroxides has been found to affect the temperature plot of the equilibrium constants of the reaction of KOH and NaOH with 2,6-di-r-butylphenol (ArOH). The nature of the cation in the resulting phenoxides ArOK or ArONa is a factor determining the kinetics of the addition of ArOH to CH2=CHC02Me. Two different kinetic schemes have been proposed to describe the transformation of ArOH in the presence of ArONa or ArOK.137... 

As noted above, the lability of the Sn-C bond is often a factor determining the outcome of such reactions and this is well illustrated in a very early reaction between Na2[Fe(CO)4] with MeSnCl3, where redistribution of methyl groups took place to form 77 and 78226. An unusual hypercoordinated tin compound 79 was obtained by reacting K[Fe(CO)3 Si(OMe)3 Ph2P(2-pyridyl ] with Cl2SnPh2, which involved an unusual silicon-tin exchange227. 

These interferences can be readily overcome by using one of the following techniques (i) The method of additions, (ii) Matching the matrix of the standards with that of the sample, (iii) Solvent extraction to remove the cation to be determined from the interfering matrix, (iv) Relating the erroneous value obtained to an accurate value by using a factor determined by other means. 

A basic weakness of the difference ratio method is that each coefficient involves a division by FL(h,A,0), which will very often be weak or even zero, leading to a large error in the coefficient. In the earlier methods, where the A-curve is explicitly determined, only the strong intensities in the pattern are used hence a reflection is scaled by a factor determined from these more precise measurements alone. 

Size can also be a factor determining which endocytotic pathways are involved in ligand absorption. For example, in nonphagocytotic cells, latex beads with diameters less than 200 nm were taken up by the clathrin-dependent pathway, and latex beads with diameters between 200 and 500 nm were taken up by a caveolin-dependent process. Similarly, absorption of DNA-polycation complexes showed clear size dependence sizes greater than 200 nm were internalized by macropinocytosis. Intermediate size... 

We also require that the theory explain the observed dependence of current on potential under various circumstances. In Chapter 1, we saw that current is often limited wholly or partially by the rate at which the electroreactants are transported to the electrode surface. This kind of limitation does not concern a theory of interfacial kinetics. More to the point is the case of low current and efficient stirring, in which mass transport is not a factor determining the current. Instead, it is controlled by interfacial dynamics. Early studies of such systems showed that the current is often related exponentially to the overpotential 7], That is. 

Hyenstrand, R, Blomqvist, R, and Petterson, A., Factors determining cyanobacterial success in aquatic systems—a literature review. Arch. Hydrobiol. Spec. Issues Advanc. LimnoL, 51, 41, 1998. 

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