Charge scavengers

In the absence of any deliberately added solution phase charge scavenger, the majority of trapped holes on Ti02 particles recombine with free conduction band or trapped photogenerated electrons however, a small fraction of the (>Ti-OH )+ sites do react to form thermodynamically stable >TiOOH or >TiOOTi< sites (vide infra) [119]. Measurement of the rate constants for these processes by photoelectrophoresis has already been reviewed elsewhere [47]. 

In the earth environment, colloidal manganese hydroxide has usually a negative electric charge, scavenging cations from the surroundings. Typical cations which react with the surface of the manganese hydroxide colloid are K, Ba, Co, Ca , Li+, NP+, Cu +, Zn +, Pb +, Fe +. ... 

Charge Scavenging during the Radiolysis of Liquid Cyclohexane. J. Chem. Phys. 43, 93 (1965). 

Comparison of the racemization induced by UV and 7-rays indicates that main-chain scission is responsible of this effect. Side chains indeed break with a much higher yield under UV than under 7-irradiation, while the reverse is true for racemization. Ethyl mercaptan inhibits main-chain scission by charge scavenging and radical repair, viz. 

This mechanism takes into account volatile and chain scission yields, the radicals identified by ESR and the results of charge scavenging and recombination obtained by absorption spectroscopy at low temperatures and thermoluminescence measurements. 

Solute fluorescence is also induced by charge scavenging followed by radical ion pair recombination... 

C. The Time Scale of Charge Recombination Charge Scavenging. . . 760... 

Solutes in the liquid, that can react with the charged species, are called charge scavengers. An example of an electron scavenger is methyl bromide ... 

As we mentioned above, the mobilities of the excess electrons given in Table 7 are all several orders of magnitude larger than those of molecular ions in these liquids. In some liquids also the positive charge has been found to have a mobility far in excess of that for a molecular ion, and which is ascribed to a fast transfer of the positive charge from the parent positive ion to the neutral molecule. This phenomenon of the electron hole has been studied by charge scavenging and by pulse radiolysis ". ... 

Generally, charge scavenging and charge geminate recombination are in competition. It has been found that in saturated hydrocarbons and often in other solvents as well, the scavenged yield can be represented by a simple expression called Warman-Asmus-Schuler equation (Warman et al. 1968,1969)... 

Freeman, G.R., 1987d, Stochastic model of charge scavenging in liquids under irradiation by electrons or photons, Kinetics of... 

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