β Scribed by Yiuchong Leung; M.Anton Walters; Racquel Z. LeGeros
No coin nor oath required. For personal study only.
Infrared absorption spectra of polycrystalline fluor-and hydroxyapatite are transformed to their second derivatives for resolution enhancement. It is observed that although the symmetry of the hydroxyapatite lattice is lower than that of fluorapatite, the spectra are nearly congruent. The data of polycrystalline samples are analysed on the basis of single crystal Raman and infrared dichroism spectra. The number of vibrational bands that are observed in the spectra of polycrystalline fluor-and hydroxyapatite exceed the number predicted by factor group analysis. The "excess" bands are assigned to vibrations that are expected to be Raman active previously reported in the single crystal Raman data of these two minerals. This can be accounted for by a breakdown of factor group selection rules as applied to the infrared data of polycrystalline apatites.
π SIMILAR VOLUMES
The IR spectra of a series of 6 phenylnitroethenes (PNE) and 6 phenylnitropropenes (PNP) were assigned, based on a normal coordinates calculation performed on styrene and styrene-d,. Some frequencies were sensitive to the electronic properties of the substituents, and others to the substitution on C
F.t.-ir. spectra of algal, bacterial, cotton, ramie, and wood celluloses, obtained in the second-derivative mode, have improved resolution. The spectra support the hypothesis that the crystalline structures of these celluloses can be divided into algal-bacterial and cotton-ran&-wood types. Bands tha
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