Localized electrical effect parameter

Ti The localized (field and/or inductive) electrical-effect parameter. It is identical to Ci. Though other localized electrical-effect parameters such as a and Op have been proposed, there is no advantage to their use. The a parameter has sometimes been used as a localized electrical-effect parameter such use is generally incorrect. 

In Eq. 71, Q is the quantity to be correlated, and is a parameter which represents the localized electrical effect. 

We believe that these results show that the ffj constants given in Table 7 constitute the best available parameters for the localized electrical effect at the present time. 

The Eo values for 2-substituted 1,4-benzoquinones (sets 45-4 through 45-7, 45-10) show an average value of pr of 59. Thus the resonance effect predominates. For most of these sets, the Op constants are not the best parameters for correlation. By contrast, the electron reduction potentials (set 45-8) show a Pr value of 39, which indicates predominance of the localized effect. The 2,5-disubstituted 1,4-benzoquinones differ distinctly in their behavior from the 2-substituted 1,4-benzoquinones in that they show an average Pr value of 53. The one-electron reduction potentials of these compounds show about the same composition of the electrical effect, with a value of Pr of 50. The only set of Eq values available for the 2,6-disubstituted 1,4-benzoquinones pve a Pr value of 51, comparable to the values observed for the 2,5-disubsti-tuted 1,4-benzoquinones. The 2,3,5,6-tetrasubstituted 1,4-benzoquinones have... 

The goodness of fit is in accord with the experimental error in the data. Both equations 42 and 43 are significant at the 99.9% confidence level. Though 07 is significantly collinear in a dependence on both parameters is fairly certain. Electrical effects are the predominant factor in the structural effect with the localized effect making the greater contribution. 

The first one is related to the local concentration gradient of admixture in the glass. The second component expresses the electric drift of admixture ions in the local electric field. This electric field can be the effect of a difference in mobility of exchanged ions. In addition to the ion exchange processes based on a purely thermal diffusion of admixture ions, some processes are also carried out in the presence of an external electric field. In such processes an additional parameter occurs the intensity of the external electric field (Fig.2). These processes are briefly called electrodiffusion. They are characterized by a directed migration of ions introduced into the glass caused by the effects of an electric field. 

The reference set must permit the defined localized effect parameters to be placed on the same scale as the and Op constants. This permits ready comparison of substituent electrical effect magnitude of systems in which the substituent is bonded to sp hybridized carbon to that in systems in which the substituent is bonded to sp or sp hybridized carbon. 

The MO measurements provide information about the angular distribution of molecules in the x, y, and z film coordinates. To extract MO data from IR spectra, the general selection rule equation (1.27) is invoked, which states that the absorption of linearly polarized radiation depends upon the orientation of the TDM of the given mode relative to the local electric field vector. If the TDM vector is distributed anisotropically in the sample, the macroscopic result is selective absorption of linearly polarized radiation propagating in different directions, as described by an anisotropic permittivity tensor e. Thus, it is the anisotropic optical constants of the ultrathin film (or their ratios) that are measured and then correlated with the MO parameters. Unlike for thick samples, this problem is complicated by optical effects in the IR spectra of ultrathin films, so that optical theory (Sections 1.5-1.7) must be considered, in addition to the statistical formulas that establish the connection between the principal values of the permittivity tensor s and the MO parameters. In fact, a thorough study of the MO in ultrathin films requires judicious selection not only of the theoretical model for extracting MO data from the IR spectra (this section) but also of the optimum experimental technique and conditions [angle(s) of incidence] for these measurements (Section 3.11.5). 

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