Germanium absorption

From equation (5.3) we see that <5A/A is approximately constant, though F(h) does vary slowly with A in the presence of absorption edges. The germanium absorption edge at 1.12 A considerably reduces the reflectivity below this wavelength. 

Ingalls R, Crozier E D, Whitmore J E, Seary A J and Tranquada J M 1980 Extended x-ray absorption fine structure of sodium bromide and germanium at high pressure J. Appl. Phys. 51 3158... 

The attenuated total reflectance (ATR) technique is used commonly in the near-infrared for obtaining absorption spectra of thin Aims and opaque materials. The sample, of refractive index i, is placed in direct contact with a material which is transparent in the region of interest, such as thallium bromide/thallium iodide (known as KRS-5), silver chloride or germanium, of relatively high refractive index so that Then, as Figure 3.f8... 

AH intrinsic germanium metal sold is specified to be N-type with a resistivity of at least 40 H-cm at 25°C or 50 H-cm at 20°C. Germanium metal prepared for use in infrared optics is usuaHy specified to be N-type with a resistivity of 4-40 Hem, to be stress-free and fine annealed, and to have certain minimum transmission (or maximum absorption) characteristics in the 3—5 or 8—12 pm wavelength ranges. Either polycrystaHine or single-crystal material is specified. 

Energy Spectrometry (EDS) uses the photoelectric absorption of the X ray in a semiconductor crystal (silicon or germanium), with proportional conversion of the X-ray energy into charge through inelastic scattering of the photoelectron. The quantity of charge is measured by a sophisticated electronic circuit linked with a computer-based multichannel analyzer to collect the data. The EDS instrument is... 

Fig. 7-6. Enhancement of the intensity of germanium radiation relative to arsenic radiation by selenium. The ordinate in this figure is, for the upper curve, the normalized Ge-As intensity ratio and, for the lower curves, the normalized absolute intensity. The abscissa is the composition of the diluent added to the base material. The relation of analytical lines and absorption edges is shown in IV, Fig. 7-5. Open circles = GeKar/AsKa closed circles = Ge crosses = As. (Courtesy of Adler and Axelrod, Spectrochim. Acta, 7, 91.)...

Ill37-42 lists the electronic absorption data for doubly bonded germanium compounds. 

The UV-vis spectral analysis confirms the appearance of a new charge-transfer absorption band of the complexes of colorless a-donors (R3MH) and the n-acceptor (TCNE). In accord with Mulliken theory, the absorption maxima (Act) of the [R3MH, TCNE] complexes shift toward blue with increasing ionization potential of the metal hydrides (i.e., tin > germanium > silicon) as listed in Table 8. 

Gastrointestinal absorption of germanium oxides and cationic salts is poor. No reports of germanium accumulation in human or animal tissue exist. 

The cyclophane 12 bridged by two silicon atoms exhibits two absorption bands with maxima at 223 nm (e = 18,400) and 263 nm (e = 22,400). Similar to 12, two absorption bands with maxima at 223 nm (e = 25,000) and 254 nm (e = 23,500) were observed for the cyclophane 17 bridged by two germanium atoms. On the other band, the cyclophane 22 bridged by two tin atoms shows an absorption band... 

The infrared spectrum of GeF2 has also been reported 10 3 It was necessary to study the matrix-isolated spectrum for two reasons. First, the examination of the ultraviolet absorption spectrum of GeF2 indicated that at least ten of the bending states were populated, and second, germanium has five abundant isotopes. These suggested that the gas phase spectrum would be broad and ill de-... 

Arachidic acid monolayers were prepared from a benzene solution on the water subphase of pH5.8(pure water) and 12.6(adjusted by addition of NaOH) at Tsp of 303 K below Tm(=328 K) of the monolayer [31]. The ionic dissociation state of hydrophilic group was estimated on the basis of the stretching vibrations of carbonyl and carboxylate groups by Fourier transform-infrared attenuated total reflection, FT-IR ATR measurements. 70 arachidic acid monolayers were transferred on germanium ATR prism, resulting in the formation of the multi-layered film. Transfer on the prism was carried out at surface pressures of 25 or 28 mN-nr1. Infrared absorption measurements revealed that almost carboxylic groups of arachidic acid molecules did not dissociate on the water subphase of pH5.8, whereas all carboxylic groups dissociated as carboxylate ions on the water subphase of pH 12.6. 

As discussed above, the measurement of characteristic y rays is very similar to the methods used in EDXRF. Early studies used a scintillation counter, typically a crystal of sodium iodide containing a small amount of thallium (Tite 1972). y ray absorption by these counters produces visible light, which is converted into an electrical pulse using a photosensitive detector. More recently semiconductor detectors have been used, either a lithium drifted germanium crystal, or, more typically, a pure ( intrinsic )... 

Table 4.2 Absorption (expressed as dimensionless /rf values) for the various beams resulting from 220 diffraction in a 1 mm thick crystal of germanium...

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