Hydrogen extinction coefficient

Hargreaves has suggested that the insolubilization of some closely related polymers is due to photolytic homolysis of the endoperoxide 0-0 bond and subsequent generation of carbon-centered radicals from the O radicals (19). There are several facts that make this an extremely unlikely explanation for the data described here these include the quantitative insufficiency of the maximum amount of endoperoxide reaction obtainable with a few hundred mJ/cm2 dose (homolysis quantum yield <0.5 (46), and extinction coefficient 1 (M cm)-1 (47)), and the synthetic utility of such homolysis reactions in related molecules in the presence of good hydrogen atom donors (implying facile epoxide formation) (48). Clearly the crosslinking observed under N2 is not accounted for by this mechanism. 

The vacuum ultraviolet photolysis of HI has been studied by Martin and Willard16 using the 1849 A mercury lines as the exciting radiation. They estimated the molar extinction coefficient at 1849 A to be between 110 and 150 in fair agreement with Romand s3 experimental value of 125. The hydrogen atoms produced have sufficient energy to cause the reaction... 

Maxima and Extinction Coefficients of the Continuous Absorption for the Hydrogen Halides (Q - N1S +)08... 

Assuming that the two carbonyl species have similar molar extinction coefficients, a simple calculation suggests that about half of the acyl radicals formed abstract hydrogen before decarbonylation. This process would thus be expected to reduce the efficiency of main-chain scission via the /3-scission mechanism. 

The stoichiometric yield of OH0 is the greatest from the photolysis of hydrogen peroxide. But - as already mentioned - the photolysis of ozone yields more OH0 than that from hydrogen peroxide because of the higher molar extinction coefficient of ozone compared to hydrogen peroxide (see Table 2-3). 

As a check on these relationships and assumptions, the extinction coefficient of the potassium monomer was obtained by directly analyzing potassium-ethylamine solutions (showing low 265 m/z absorption) by determining hydrogen evolution following addition of water. This gave 6 = (4.9 =t 0.7) X 104 at 650 m/z and —78° C., which is quite close to the photoregeneration value and somewhat more reliable. 

Human serum transferrin and chicken ovotransferrin have been reported to bind cobalt, iron, copper, zinc, and manganese. The iron complex is red with an absorption maximum at 465 mp.. Complexes of copper and manganese are yellow. Ulmer and Vallee (128) formed a complex with Mn3+ by standing for 12 hours while Inman (68) formed a complex by addition of hydrogen peroxide to a mixture of Mn2+ and the transferrins. Absorption spectra for three of the colored complexes of human serum transferrin are given in Fig. 5. Extinction coefficients are listed in Table 9. 

Haloperoxidase activity is usually determined spectrophotometri-cally by the bromination or chlorination of 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (monochlorodimedone MCD) using hydrogen peroxide as the oxidant of the halide (28) (Figure 2). This assay is convenient because of the large change in extinction coefficients between the enolate and the product. However, its use is constrained by the need for conditions that stabilize the enolate. In the early work on V-BrPO, the... 

M hydrogen bromide. The tribromide can be determined spectrophotometrically at 275 nm. At this wavelength, perbromic acid has an extinction coefficient of only about 5.8... 

The measured shift of A from point 1 to 2 in Fig. 11.7 can be understood by assuming that a surface layer of the hard C D film (point 1 to 1) is transformed into a polymer-like C H D film (point 1 to 2) due to adsorption of CH3 radicals at sp2-coordinated carbon groups at the initial film surface it is assumed, that this reaction is similar to the hydrogenation of sp2 carbon groups by atomic hydrogen, which changes the hybridization of the sp2 CC bond to sp3 [53]. The extinction coefficient at 632.8 nm is related to the... 

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