Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Energetic levels

The electronic influence on the donor ability of the monomers as well as the acceptor behavior of the corresponding cation has been characterized by variation of the para-substituents of the styrenes. More detailed assertions can be expected when one varies the structure directly on the double bond by substitution at a- and P-position. A suprisingly good correlation appears between the energetic level of the HOMO and energy of theCT-absorption of the complexes with TCNE (ECT = 20.8 5.55x(HOMO) r = 0.80 n = 12) for styrenes, both with and without a methyl substituent at a- and p-position ... [Pg.201]

Table 15. Energetic levels of the HOMO of X, SbX6 and Sb2Xn (all values in eV)... Table 15. Energetic levels of the HOMO of X, SbX6 and Sb2Xn (all values in eV)...
Theoretical calculations demonstrated that the energy gap between HOMO and LUMO levels is not particularly affected by pH variations, but a systematic downshift is recorded with increasing pH. The energetic levels are not influenced by the substituent, which is usually a glucosidic unit, even though has been widely demonstrated that it increases dye stability [34]. [Pg.247]

The tetrahedral structure of these surface alkyl complexes on MCM-41(5oo) has been highlighted by XANES a sharp, intense pre-edge peak at 4969.6 0.3 eV is characteristic of an electronic transition of titanium, from the Is energetic level to molecular orbitals mixing 3d and 4p of Ti with the orbitals of the Ugands, in a complex where titanium is in a tetrahedral symmetry [28-31]. The same argument can be applied for species obtained from alcoholysis of 2a and 2b, especially using tert-butanol. [Pg.31]

Photoconductivity is one of the most informative phenomena in semiconductor physics. The light beam enables us to exite definite energetic levels strongly and obtain information about photogeneration, recombination and transport processes of the charge carriers. The history of photoconductivity shows the every essential step in research and application has been linked with the appearance of new photosensitive materials with specific physico-chemical properties. [Pg.5]

Fig. 48. Scheme of the energetic levels of polycopperphenylacetylenide and dyes [279], cp -photoelectrical work function, AE - the energy of the absorption edge, % - electron affinity (all data are in eV)... [Pg.70]

Obviously, intermediates, which are formed in the gaseous phase, arise as a result of the strong electrostatic attraction of species with no solvation. Calculations predict that mixing of the nitronium ion with benzene causes an interaction of frontal molecular orbitals. As a result, their energetic levels are changed. At a distance between the reagents of from 0.025 to 0.015 nm, an electron transfer is possible, even from benzene to the nitron-... [Pg.261]

Although the two competing intermediates, the hypothetical ketyl-aryl radical pair (4) and the oxaspirooctadienyllithium (3), are not the rate-determining transition states, they should lie at almost the same energetic level. The rearrangement is in accord with the intramolecular nucleophilic addition/elimination mechanism rather than with homolytic cleavage/recombination. [Pg.452]

The detailed analysis of the results shows that the main properties of the P electronic structure are qualitatively independent of the P-P distance. So in the case (a) the order of the energy of the mono-electronics levels and the distribution of the electrons on energetic levels (Table 2) are similar to that presented in Fig. 1 for the experimental distance R p. [Pg.403]

Third, the existence of regular periodic structure leads, when an additional electron moves along such structure, to quantization of it energy (due to Flocke theorem). The quantization leads to additional energetic levels in carbon nanotube spectrums and may also lead to suppression of electron-phonon interaction (if energy levels enough separate from phonon spectrum) and to increasing of carbon nanotubes conductivity. Especially appreciably it can be shown in case of low temperatures at sufficient electron concentration. [Pg.479]

If finally both, reaction products and reactants, are present in the system at equal energetic levels (there is no difference between the free energies of products and reactants) no reaction can occur in any direction. In such a case we speak of an equilibrium between the reactants and the reaction products, which can be expressed (at condition of constant temperature and pressure) by the following equation ... [Pg.50]

The effects of the Stone are quite powerful, both at the physical level and at the energetic level. Like the Ens Tinctures, the Vegetable Stone is held to possess an initiatic virtue that can bring an awareness of Nature s operations by opening the subtle energy flow... [Pg.45]

In the work described here, we have dedicated special emphasis not only to the characterization of fhe low lying energetic levels, but also to the associated wavefunctions exploiting the availability of realistic potential energy surfaces. This study completes the faithful picture of the internal dynamics of the system involving levels pertaining to the lowest energy states for the dimers. [Pg.318]

However, there are ways to determine energetic levels in some molecule or complex, including changes which occur by replacing some substituent (or in... [Pg.33]


See other pages where Energetic levels is mentioned: [Pg.152]    [Pg.160]    [Pg.424]    [Pg.207]    [Pg.201]    [Pg.36]    [Pg.261]    [Pg.220]    [Pg.122]    [Pg.356]    [Pg.696]    [Pg.17]    [Pg.25]    [Pg.70]    [Pg.1466]    [Pg.66]    [Pg.668]    [Pg.356]    [Pg.442]    [Pg.190]    [Pg.49]    [Pg.277]    [Pg.100]    [Pg.97]    [Pg.53]    [Pg.452]    [Pg.1355]    [Pg.829]    [Pg.167]    [Pg.149]    [Pg.174]    [Pg.229]    [Pg.231]    [Pg.234]   


SEARCH



Energetics Levels

Energetics Levels

Energetics and electronic levels

Semiconductors energetic levels

© 2024 chempedia.info