Energy trapping

Fig. 18. Trapping energy from absorbed light in a band gap trap (5).

Color from Color Centers. This mechanism is best approached from band theory, although ligand field theory can also be used. Consider a vacancy, for example a missing CF ion in a KCl crystal produced by irradiation, designated an F-center. An electron can become trapped at the vacancy and this forms a trapped energy level system inside the band gap just as in Figure 18. The electron can produce color by being excited into an absorption band such as the E transition, which is 2.2 eV in KCl and leads to a violet color. In the alkaU haUdes E, = 0.257/where E is in and dis the... 

Trapped energy gets discharged into the healthy leeders/circuits... 

Figure 6.35 Trapped energy distribution of a large feeding source during a fault clearing by a current-limiting device...

L2- Inductor to absorb the trapped energy up to Ic)[par1ly absorbed by the feeder s own impedance and ofher feeders... 

Figure 6.36 Use of induclor on the supply side of a static drive to absorb the trapped energy...

In the classical limit where the condition << kgT is met for the trapping vibrations, the rate constant for electron transfer is given by eq. 6. In eq. 6, x/4 is the classical vibrational trapping energy which includes contributions from both intramolecular (X ) and solvent (XQ) vibrations (eq. 5). In eq. 6 AE is the internal energy difference in the reaction, vn is the frequen-... 

The concept of color centers has been extended to surfaces to explain a number of puzzling aspects of surface reactivity. For example, in oxides such as MgO an anion vacancy carries two effective charges, V(2. These vacancies can trap two electrons to form an F center or one electron to form an F+ center. When the vacancy is located at a surface, the centers are given a subscript s, that is, Fs+ represents a single electron trapped at an anion vacancy on an MgO surface. As the trapping energy for the electrons in such centers is weak, they are available to enhance surface reactions. 

Ion-trap Energy and spatial distribution of ions produced in the ion source is not critical Inherent tandem MS capabilities for generation of sub-structure information Low cost and easy to couple to LC Vacuum demand is minimum Low resolution and low accuracy in mass measurement... 

Bachu, S., Gunter, W. D. Perkins, E. H. 1994. Aquifer disposal of C02 hydrodynamic and mineral trapping. Energy Conversion and Management, 35, 269-279. 

Equation (9) shows that for a1 independent of T, measurement of the emission rate as a function of temperature yields the trap energy. The temperature dependence of > (oc T1/2) and Nc(cc T3/2) can be taken into account either by determining the slope of ln(e, /T2) as a function of 1/T or by subtracting 2kTm from the slope of In e versus 1/T, where Tm is the average temperature over which the slope of In e was measured (Miller et ai, 1977). However, a is often temperature dependent. For instance, Henry and Lang (1977) show that it frequently can be represented by... 

The above analyses show the qualitative agreement of the adsorption model with recent conductivity experiments, and indicate how the trapping energy in adsorption may be indirectly obtained by conductivity measurements in the temperature range where slow desorption occurs. The energy can be obtained accurately, however, only with more careful examination of the theory and experiment than is presented here. 

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