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Quantum apparent differential

Apparent differential quantum yield The apparent differential quantum yield... [Pg.16]

Apparent NMR equivalence of nuclei can also arise by a quantum mechanical intramolecular tunneling process. In principle, this process may be differentiated from intermolecular exchange processes because although the exchanging nuclei are rendered equivalent insofar as the NMR experiment is concerned, spin-spin splitting by other magnetic nuclei is not washed out. This type of intramolecular exchange is manifested in several boron hydride derivatives. It was first proposed by Ogg and Ray (98) to explain the NMR spectra of aluminum borohydride, whose structure is... [Pg.264]

One of the most important features of a photoreaction is the value of the quantum yield ( )i of compound i, which is the quantifying answer to the question How effective In principle, the quantum yield is the ratio of the number of reacting molecules to the number of quanta absorbed. In praxis there are several definitions of the quantum yield true (only light absorbed by the reactant is considered) and apparent (there are other absorbers present), differential (at the moment ) and integral (mean). In the previous rate equation, ( )e and (j) are the true differential yields. The monoexponential kinetics of Equation, 1.2 or 1.4 allow one to determine the yields in systems where the starting solution is already a mixture of E- and Z-forms (which can happen easily if the E-form is not prepared under strict exclusion of light). It turns out, however, that the yalues of the Z —> E quantum yield are especially sensitive to small errors in the E values. [Pg.10]

The fractional derivative technique is used for the description of diverse physical phenomena (e.g., Refs. 208-215). Apparently, Blumen et al. [189] were the first to use fractal concepts in the analysis of anomalous relaxation. The same problem was treated in Refs. 190,194,200-203, again using the fractional derivative approach. An excellent review of the use of fractional derivative operators for the analysis of various physical phenomena can be found in Ref. 208. Yet, however, there seems to be little understanding of the relationship between the fractional derivative operator and/or differential equations derived therefrom (which are used for the description of various transport phenomena, such as transport of a quantum particle through a potential barrier in fractal structures, or transmission of electromagnetic waves through a medium with a fractal-like profile of dielectric permittivity, etc.), and the fractal dimension of a medium. [Pg.237]

Hence, one should differentiate the fact that the approach of Clar apparently lacks a tangible connection to quantum chemistry from assumptions that it contradicts quantum chemistry — as it does not ... [Pg.101]

In the quantum-chemical study the probability of molecule ionization at TP decomposition, for example, by proton detachment, was also taken into account. In the frames of semi-empirical FNDO/2 method (Full Neglecting of Differential Overlapping) the energy of H detachment (Table 3) was calculated by the difference between total electron energy of the molecule and energy of its negative ion (tf detachment). These observations do not correlate in any way with the experimental data on thermal stability. This, apparently, removes the problem of ionic state participation in the degradation process. [Pg.111]


See other pages where Quantum apparent differential is mentioned: [Pg.421]    [Pg.345]    [Pg.86]    [Pg.437]    [Pg.132]    [Pg.81]    [Pg.339]    [Pg.1326]    [Pg.215]    [Pg.1425]    [Pg.3084]    [Pg.3085]    [Pg.37]    [Pg.28]    [Pg.88]   
See also in sourсe #XX -- [ Pg.16 ]




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