Edge method

Fig. 5—4. Analysis by the absorption-edge method. The solid lines are photometric measurements of a photograph of the x-ray intensity as a function of angle. The concentration is calculated from the ratio of these lines extrapolated to the absorption edge. Table 5-4 gives some typical results.

A few general remarks about the absorption-edge method are in order here. For any element, only two absorption edges, the K and the Lm... 

Finally, it is obvious that the absorption-edge method will often be at... 

Later work oft the absorption-edge method was restricted to one measurement on each side of an edge. At Oak Ridge, Barringer and 18 H. A. Liebhafsky, Anal. Chem., 22, 15 (1950). 

See the end of Section 5.3. Various investigators have used differential absorptiometry at two wavelengths that enclose, but do not locate, an absorption edge. This procedure resembles simple absorptiometry at more than one wavelength, and it also resembles the absorption-edge method. 

Angstrom unit (A), definition, 307 Antimony, determination by x-ray emission spectrography, 328 in silicate, determination by absorption-edge method, 140 in solution, determination by absorption-edge method, 140 Aperture, relative, of x-ray optical system, 113... 

Broadening, of monochromatic beams by crystals, 115, 116, 118 of pulse-size range, 47 Bromine, as internal standard in tungsten analysis, 194-196 determination, by absorption-edge method, 138-142... 

Calcium, determination by x-ray emission spectrography, 222, 328 in biological samples, determination by monochromatic x-ray absorption-edge method, 299-301 in biological sections, determination by x-ray absorption-edge method, 293, 294... 

Uranium, in solution, determination by x-ray absorption-edge method, 142, 143... 

A collection of cutting-edge methods intended to provide practical guidelines for those who are new to the area of separations in two-phase systems has been published by Hatti-Kaul [29]. 

Fig. 10. Adsorption energy of CO on NiO(lOO) cleaved in vacuum as a function of coverage. The data have been determined from TDS spectra like those shown in Fig. 6 (upper part) using the leading edge method and complete analysis. TDS data taken with heating rates of 0.1, 0.2, 1 and 2 K/s have been used.

Numerous compounds have also been investigated by means of the X-ray absorption edge method (11, 12, IS, 113). This allows one to identify the lowest free p-orbitals which can be occupied by excited Is electrons. The results obtained for ferrocene in the solid state, in solution in solvents of different polar character, and in the vapor phase, are... 

Among the cutting-edge methods and studies reviewed in this decennial volume of the series are the Density Functional Theory DFT method, vibrational electron energy loss spectroscopy EELS), computational models of the reaction rate theory, the nuclear magnetic resonance triplet wavefunction model (NMRTWM) and biological reactions that benefit from computational studies. 

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