Resonant electron transfer

Resonant processes of some importance include resonant electronic to electronic energy transfer (E-E), such as the pumping process of the iodine atom laser... 

A third pumping method (Fig. Ic) uses an electrical discharge in a mixture of gases. It relies on electronic excitation of the first component of the gas mixture, so that those atoms are raised to an upper energy level. The two components are chosen so that there can be a resonant transfer of energy by collisions from the upper level of the first component to level 3 of the second component. Because there are no atoms in level 2, this produces a population inversion between level 3 and level 2. After laser emission, the atoms in the second component return to the ground state by collisions. 

The resonant frequency of the crystal is inversely proportional to the mass of the Pmssian blue coating. When the immobilized enzyme acts on its substrate, glucose-6-phosphate [54010-71-8] (4), electrons are transferred to the Pmssian blue. In order to maintain electrical neutraUty, cations... 

When the polydisperse silver nanoparticles are irradiated with a monochromatic light, only the nanoparticles that are resonant with the incident light are excited and the excited electrons are transferred to Ti02, giving rise to liberation of Ag. The resonant particles are thus reduced in size until they become non-resonant. Some of the electrons... 

Nonradiative transfer of excitation energy requires some interaction between donor and acceptor molecules and occurs if the emission spectrum of the donor overlaps the absorption spectrum of the acceptor, so that several vibronic transitions in the donor must have practically the same energy as the corresponding transitions in the acceptor. Such transitions are coupled, i.e., they are in resonance, and that is why the term resonance energy transfer (RET) or electronic energy transfer (EET) are often used. 

The theory of resonance transfer of electronic excitation energy between donor and acceptor molecules of suitable spectroscopic properties was first presented by Forster.(7) According to this theory, the rate constant for singlet energy transfer from an excited donor to a chromophore acceptor which may or may not be fluorescent is proportional to r 6, where r is the distance... 

This is called a chemical, radical or stepwise mechanism. Or was it (ii) by the action of the bridging group to increase the probability of electron transfer by tunneling, termed resonance transfer 56,9i... 

There are three possible mechanisms whereby an excited atom or ion can undergo an electronic transition near a metal surface (1) de-excitation involving the emission of radiation, (2) de-excitation involving a two electron Auger process, and (3) a resonance process whereby an electron is transferred from the metal to an equivalent energy level in the ion or a similar transition where the electron goes from the ion to the metal. However, Schekhter has shown that the probability... 

Finally—and I think the subject is becoming ripe for development on this level —let us turn to the question of the mechanisms by which electron transfer takes place. One important distinction is whether the electron transfers by a resonance mechanism or by a chemical one. Different observations can be made depending on this difference in mechanism. Perhaps one of the most significant is based on the fact that if there is resonance transfer, preparation for receiving the electron will be made at the Co(III) center, but if the electron transfers to the ligand, this kind of preparation at the metal ion center is not required. An experimental approach to distinguish between the two cases may be this when Co (111) receives the electron directly, there may be a strong discrimination between the isotopes of... 

Harry Gray Two points in Prof. Taube s paper quoted as experiments in progress haven t been mentioned. Both are concerned with the mechanism of electron transfer, because the transmission in the ligand, wherever the attack is, is through the 7r-system, and in cobalt(III) in the detectable radical ion intermediate, because of the improbability of resonance transfer from tt to electron resonance experiment in which one tries the reduction by chromous and looks for the ESR signal of the radical ion. 

The electronic excitation discussed up to this point involves translational to electronic energy transfer. Of great practical importance is near-resonant electronic excitation-energy transfer, which leads to ion lasers in the He-Kr and Ne-Xe systems.294 The reactions involved are (He and Ne ... 

Diffuse reflectance spectroscopy (DRS) of VO-porphyrins on reduced and sulfided catalysts exhibit shifts in the porphyrinic electronic spectra (Soret, a, (3 bands) to higher frequencies. Adsorption results in modification of the delocalized electronic resonance structure not observed on the oxide form of the catalyst. X-ray photoelectron spectroscopy reveals shifts to higher Mo binding energies on reduced and sulfided catalysts following VO-porphyrin adsorption, consistent with transfer of electrons from Mo electron donor sites to the V02+ ion. Interaction at the electron donor sites is stronger than interaction at electron acceptor sites typical of the oxide catalyst. This gives rise to the possibility of lower VO-porphyrin diffusion rates on sulfided catalysts, but this effect has not been experimentally demonstrated. 

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