Electronic reaction flux

When an electronation reaction is occurring at an interface, the equality of the charge-transfer flux and the transport flux requires that... 

Reviews of the Cope reaction, electronic quantum fluxes during the rearrangement of semibullvalene," the chemistry of hetero-substituted isocyanates and isothiocyanates RX-NCY (X = R2N, RO, RS Y = 0, S) and the isomeric cyanates RX-OCN, thiocyanates RX-SCN, nitrile oxides RX-CNO, and nitrile sulfides RX-CNS have appeared. ... 

The irreversibihty of the electrochemical reactions arises from the reaction overpotential at the interface and can be given hyjr. The Joule heating can be derived by considering the local protonic or electronic current flux, or... 

As an analysis of this laser control of chemical reaction in terms of electron dynamics, in Figs. 8.5 and 8.6 we present the snapshots of electron current flux and corresponding time derivative of electron density at the time 15 and 25 fs for the cases with the pulse width = 4.84 fs starting from the asymptotic ground (Na+Cl) and first excited (Na+- -Cl ) states. Due to the non-resonance for electronic transition as well as medium strength of the laser field, complicated interference patterns are found in the spatial distribution of the flux and in the time derivative of electron density. 

Andrae D, Barth I, Bredtmann T, Hege H-C, Manz J, Marquardt F, Paulus B (2011) Electronic quantum fluxes during pericyclic reactions exemplifled for the cope rearrangement of semibullvalene. J Phys Chem B 115 5476... 

If the molecules could be detected with 100% efficiency, the fluxes quoted above would lead to impressive detected signal levels. The first generation of reactive scattering experiments concentrated on reactions of alkali atoms, since surface ionization on a hot-wire detector is extremely efficient. Such detectors have been superseded by the universal mass spectrometer detector. For electron-bombardment ionization, the rate of fonnation of the molecular ions can be written as... 

The proposed model for the so-called sodium-potassium pump should be regarded as a first tentative attempt to stimulate the well-informed specialists in that field to investigate the details, i.e., the exact form of the sodium and potassium current-voltage curves at the inner and outer membrane surfaces to demonstrate the excitability (e.g. N, S or Z shaped) connected with changes in the conductance and ion fluxes with this model. To date, the latter is explained by the theory of Hodgkin and Huxley U1) which does not take into account the possibility of solid-state conduction and the fact that a fraction of Na+ in nerves is complexed as indicated by NMR-studies 124). As shown by Iljuschenko and Mirkin 106), the stationary-state approach also considers electron transfer reactions at semiconductors like those of ionselective membranes. It is hoped that this article may facilitate the translation of concepts from the domain of electrodes in corrosion research to membrane research. 

This reaction was also used to deposit epitaxial silicon at the temperature range of 1000-1040°C, but the deposit was generally unsatisfactory and the reaction is no longer used for that purpose. However, if the reaction is enhanced with a plasma using electron cyclotron resonance (ECR), fluxes may be independently controlled and high-quality epitaxial silicon deposits are obtained at temperatures below 500°C.P 1... 

The above statements are valid for monomolecular layers only. In the case of polymer films with layer thickness into the p-range, as are usually produced by electropolymerization, account must also be taken of the fact that the charge transport is dependent on both the electron exchange reactions between neighbouring oxidized and reduced sites and the flux of counterions in keeping with the principle of electroneutrality Although the molecular mechanisms of these processes... 

Figure 25. Electron-transfer rate the electronic coupling strength at T = 500 K for the asymmetric reaction (AG = —3ffl2, oh = 749 cm ). Solid line-present full dimensional results with use of the ZN formulas. Dotted line-full dimensional results obtained from the Bixon-Jortner formula. Filled dotts-effective ID results of the quantum mechanical flux-flux correlation function. Dashed line-effective ID results with use of the ZN formulas. Taken from Ref. [28].

The power dissipated at two different frequencies has been calculated for all reactions and compared with the energy loss to the walls. It is shown that at 65 MHz the fraction of power lost to the boundary decreases by a large amount compared to the situation at 13.56 MHz [224]. In contrast, the power dissipated by electron impact collision increases from nearly 47% to more than 71%, of which vibrational excitation increases by a factor of 2, dissociation increases by 45%, and ionization stays approximately the same, in agreement with the product of the ionization probability per electron, the electron density, and the ion flux, as shown before. The vibrational excitation energy thresholds (0.11 and 0.27 eV) are much smaller than the dissociation (8.3 eV) and ionization (13 eV) ones, and the vibrational excitation cross sections are large too. The reaction rate of processes with a low energy threshold therefore increases more than those with a high threshold. 

As mentioned above, the distribution of the various species in the two adjacent phases changes during a potential sweep which induces the transfer of an ion I across the interface when the potential approaches its standard transfer potential. This flux of charges across the interface leads to a measurable current which is recorded as a function of the applied potential. Such curves are called voltammograms and a typical example for the transfer of pilocarpine [229] is shown in Fig. 6, illustrating that cyclic voltammograms produced by reversible ion transfer reactions are similar to those obtained for electron transfer reactions at a metal-electrolyte solution interface. 

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