Fluctuation band

In the fluctuation band of electron energy of hydrated redox particles, the donor band of the reductant is an occupied band, and the acceptor band of the oxidant is a vacant band. The level erotsDcno at which the donor state density equals the acceptor state density (Aai/e) = Dox(e)) is called the Fermi level of the redox electron by analogy with the Fermi level e, of metal electrons [Gerischer, 1961]. From Eqns. 2—48 and 2—49 with f BED(e) =-DoxCe), we obtain the Fermi level Tiixxox.) (the redox electron level) as shown in Eqn. 2-51 ... 

Figure 2-41 compares the electron level diagram of intrinsic semiconductors with that of hydrated redox particles at the standard concentration. The two diagrams resemble each other in that the Fermi level is located midway between the occupied level and the vacant level. It is, however, obvious that the occupied and vacant bands for semiconductors are the bands of delocalized electron states, whereas they are the fluctuation bands of localized electron states for hydrated redox particles. 

Supersonic expansions have been used to form small metal aggregates, (2 < n < 4). Emphasis is placed on the analysis of bound-free transitions in these small metal clusters. Discussion focuses on the characterization of variously produced sodium supersonic expansions and the analysis of laser Induced atomic fluorescence resulting from the photodissociation of triatomic sodium clusters. We will consider (1) the nature of observed "fluctuation" bands corresponding to bound-free transitions involving a repulsive excited state which dissociates to yield (Na-D line) sodium atoms and ground state,, ... 

Laser Induced Atomic Fluorescence and Sodium Trimer Fluctuation Bands... 

The Ps 2 Na fluorescence varies with laser frequency, producing a series of fluctuation bands extending from 17500 to 19700 cm Figure 7 presents the continuation of the spectra in Figure 6 in order, an excitation spectrum dominated by the Na2 B-X system, P3/2 laser induced atomic fluorescence, Pi/2 fluorescence, and appropriate photoluminescence spectra which at higher frequencies correspond in large part to the B-X system. 

The intensities of the 83/2 and Pi/2 fluctuation bands in Figure 8 are in the ratio 2 to 1, virtually a statistical distribution however, the relative Intensity distributions for the Pi/2 and Pa/2 fluctuation bands differ notably. Much more pronounced differences are observed for the "hot bands" depicted in Figures 6 and 7 where the P3/2/ Pi/2 ratio varies with exciting frequency and in many instances approaches 8/1. This difference in intensity ratio must reflect very different geometries for the lower discrete states from which pumping occurs in bound-free transition. Again such a result would appear to correlate well with the theoretical analysis of the sodium trimer surface. Martin and Davidson predict that a linear symmetric conformation lies only 1050 cm above the ground... 

Figure 8 Free energy surfaces for the precursor and successor states of intramolecular electron transfer in a model charge-transfer system. " On the plot the dashed fines indicate the Marcus theory, circles are simulations, and solid lines refer to the Q-model. The vertical dashed line marked Xq indicates the hoimdary of the energy gap fluctuation band predicted by the Q-model. (Reprinted with permission from Ref 54, 1989 American Chemical Society)...

Fig. 5. Fluctuating band edges of amorphous semiconductors arising from compositional or structural inhomogeneities. A typical eigenstate near the conduction band edge is shown transport of conduction electrons involves tunneling between neighboring minima or thermal activation.

The structure of the surface layers was investigated by IR spectroscopy of disturbed total reflection at the polyurethane film specimens based on OTMG, 2,4-TDI, and 4,4 -diamino-3,3 -dichlorodiphenyl-methane, filled with ADEG. To describe the change in the absorption band with change of filler content, optical densities were determined in accordance with the baseline method. The valence and deformation fluctuation bands of CH2 groups at 2860 and 1370 cm and of benzene rings at 1600 cm were used as an internal standard. 

Detection limits are defined as the concentrations (fig/mi) required to produce a signal level at least twice as great as the standard deviation of the total background noise fluctuations. Band emission observed. 

Keywords Perovskite distortions. Magnetic configurations. Fluctuation band narrowing. Interatomic exchange... 

Moreover, shift of the ACP substantially increases the density of states (DOS) at FL, HaiEp) = d /dk)p, and induces corresponding decrease of effective electron velocity d /dk)Ep of fluctuating band in this region of k-space. Physically, it represents the system transition from adiabatic (0Ep, or even to a strongly anti-adiabatic state with (O Ep. This effect has crucial theoretical impact. Not only is the ME approximation not valid (impossible to calculate non-adiabatic vertex corrections which represent off-diagonal corrections to the adiabatic ground state), but the adiabatic BOA itself does not hold. 

Close to the fc-point where the original band, which interacts with fluctuating band, intersects FL, the occupied states near FL are shifted downward below FL and unoccupied states are shifted upward - above FL. The gap is identified as the energy between peaks in the corrected DOS above FL (half-gap) and below FL. The formation of peaks is related to the spectral weight transfer that is observed by ARPES or tunneling spectroscopy in cooling below Tc. 

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