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O 7 were measured. The temperature dependence of phonons was studied in the range 4-295 K. The discussion of the results is based on the factor group approach for the tetragonal P42 1 m (D 3 2d ) space group with Z = 2. The discussion of the internal vibrations of the Ge 2 O 7 unit and external modes is made on the basis of the literature data and phonon calculations. The results obtained for the spontaneous Raman scattering were used in the discussion of the stimulated Raman spectra of the studied materials.

Articles you may be interested inCopper doping of ZnO crystals by transmutation of 64Zn to 65Cu: An electron paramagnetic resonance and gamma spectroscopy study The X-band electron paramagnetic resonance spectra of Cu+ + ions doped into amorphous, tetragonal, and hexagonal Ge02 have been observed at 295°K. Optical absorption and reflection data for, respectively, the doped glass and polycrystaIIine samples were also obtained. From the experimental results, the symmetry of the cupric complexes and some characteristics of the metal ion's bonding are deduced. In amorphous and tetragonal Ge02, the Cu+ + ions are basically in sixfold coordination. Because these cupric complexes exhibit a significant axial distortion (elongation), however, they have been treated as having square planar symmetry. Since the host cations in amorphous Ge02 are tetrahedrally coordinated, the presence of square planar Cu+ + complexes suggests that, to a significant extent, the cupric ions determine their immediate environment in the glassy host. The Cu+ + ions in hexagonal Ge02 appear to be located within the system of oxygen channels (tunnels) which are present in this crystal.1. SIEGEL AND J. A. LORENC

Thirteen edible oils: sunflower, avocado, hemp, high-linolenic flax, low-linolenic flax, safflower, walnut, roasted sesame, rice, corn, rapeseed, pumpkin seed, and hazel were studied in this work. Their fatty acid composition, iodine, acidic, peroxide, and saponification values were determined. Infrared and Raman spectra of the oils were recorded in the range 400-3200 cm −1 . The integral intensities of the bands at about 1655 and 2852 cm −1 corresponding to ν(C=C) and ν(CH 2 ) vibrations were evaluated and used to construct a relationship between the spectroscopic data and the iodine value. The following linear dependencies were obtained: I ν(C=C) /I ν(CH2) = 7.449 × 10 −4 × iodine value -0.0339 and I ν(C=C) /I ν(CH2) = 9.299 × 10 −4 × iodine value -0.023 for the infrared and Raman spectra with a correlation coefficient 0.988 and 0.976, respectively. These calibration lines can be used to determine the iodine value for oils with unknown unsaturation level, and may be applied for margarines and other fatty materials.

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