Pulse radiolysis defined

Pulse radiolysis results (74) have led other workers to conclude that adsorbed OH radicals (surface trapped holes) are the principal oxidants, whereas free hydroxyl radicals probably play a minor role, if any. Because the OH radical reacts with HO2 at a diffusion controlled rate, the reverse reaction, that is desorption of OH to the solution, seems highly unlikely. The surface trapped hole, as defined by equation 18, accounts for most of the observations which had previously led to the suggestion of OH radical oxidation. The formation of H2O2 and the observations of hydroxylated intermediate products could all occur via... 

The optical absorption spectra of sulfonyl radicals have been measured by using modulation spectroscopy s, flash photolysis and pulse radiolysis s techniques. These spectra show broad absorption bands in the 280-600 nm region, with well-defined maxima at ca. 340 nm. All the available data are summarized in Table 3. Multiple Scattering X, calculations s successfully reproduce the experimental UV-visible spectra of MeSO 2 and PhSO 2 radicals, indicating that the most important transition observed in this region is due to transfer of electrons from the lone pair orbitals of the oxygen atoms to... 

Quantities of pyridinyl radicals are best prepared by chemical reduction, defined concentrations of radicals by electrochemical reduction, by photolytic procedures, or by pulse radiolysis in aqueous solution. 

Parent radical cations derived from alkanes and alkyl chlorides can be directly observed in the nanosecond time domain by time-resolved spectroscopy such as laser flash photolysis and electron pulse radiolysis. Especially the latter one enables the direct ionization of the solvents independently on the optical properties of the sample and a well-defined electron transfer regime according to Eq. (2) or (3). Representative examples of the radiolyfic generation of solvent radical cations are given in Eqs. (4) and (5a) for the cases of 1-chlorobutane and -decane. ... 

Although electrochemical CO2 incorporation into unsaturated hydrocarbons is a significant advancement, it is not economical to fix CO2 in this manner. We are interested in using Ni(bpy)3 to photochemically reduce CO2. We have found that when an MeCN solution containing Ni(bpy)3, triethylamine (TEA), and CO2 is irradiated at 313 nm, it produces CO with a quantum yield of-0.1% (defined as CO produced/photons absorbed). Here we present results on photochemical CO2 reduction using Ni(bpy)3 and discuss the nature of the various intermediates studied by electrochemistry, flash photolysis, and pulse radiolysis. 

The prompt formation of the "satellite ions" introduces ambiguity in the measurement of the hole mobility in pulse radiolysis. Indeed, the conductivity is a product of the mobility and the yield [8]. The latter quantity is poorly defined since the branching ratio fh between the high-mobility solvent holes and the "satellite ions" is unknown. 

Fe is replaced by Ce. The 1- and m- species are different in defined radicals (Kirino and Kwan, 1971 1972). The absorption spectra of L-AA free radicals generated in aqueous solution (pH, 0.3 to 11) by pulse radiolysis were studied. Variation in Extinction Coefficient with pH suggested that... 

In general these data are comparible with the absorption spectra of thiyl radicals detected by the pulse radiolysis technique in dilute aqueous solutions [10, 56-58]. The spectra typically display fairly weak and poorly resolved absorption with a maximum around 330 nm. The only species showing a well-defined absorption maximum is the radical derived from penicillamine... 

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