Principles of NIR SpectroscopyAs has been previously mentioned, NIR spectroscopy is concerned with both electronic and vibrational transitions. 1−15 It should be noted that it is rather difficult to differentiate electronic transitions in the Vis region and those in the NIR region. What one can say, however, is that most of the electronic transitions observed in the NIR region are d-d

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South Parks Road, Oxford OX1 3QYStructural investigation of the products obtained by microbiological hydroxylation of substrates in the androstane, pregnane, and mstrane series has involved examining the l H n.m.r. spectra of 344 steroids, 243 of them being new compounds. Mild oxidation of the products gives polyketones in which the positions of the oxo-groups are characterised by the chemical and solvent shifts of the 18-H and 19-H signals. This information is supplemented by the chemical shifts of the products' 18-H and 19-H signals, and by the positions and form of their )CH-OH resonances : the latter are especially useful in establishing the configurations of the hydroxy-groups.FOR the past five years we have been studying the hydroxylation of mono-and di-oxygenated steroids with a range of micro-0rganisrns.l The intention was to vary the positions of the oxygen substituents around the steroid nucleus in a systematic manner: it was -gate, ibid., 1969, 463. hoped that the use of relatively simple substrates would facilitate interpret at ion of the microbiological behaviour. A considerable body of results has accrued from examining monoketones, keto-alcohols, and diketones derived from handrostane, 5a-pregnane, and 5a-cestrane ; a series of papers describing the work will be submitted shortly to this Journal. The preparation of substrates and related chemical studies are being recorded in a separate series2

Low-frequency vibrational bands observed in the Raman and terahertz (THz) spectra in the region of 50-150 cm(-1) of crystalline powder poly-(R)-3-hydroxybutyrate (PHB) were assigned based on comparisons of the Raman and THz spectra, polarization directions of THz absorption spectra, and their congruities to quantum mechanically (QM) calculated spectra. This combination, Raman and THz spectroscopies and the QM simulations, has been rarely adopted in spite of its potential of reliable assignments of the vibrational bands. The QM simulation of a spectrum has already been popular in vibrational spectroscopies, but for low-frequency bands of polymers it is still a difficult task due to its large scales of systems and a fact that interactions among polymer chains should be considered in the calculation. In this study, the spectral calculations with the aid of the Cartesian-coordinate tensor transfer (CCT) method were applied successfully to the crystalline PHB, which include the explicit consideration of an intermolecular interaction among helical polymer chains. The agreements between the calculations and the experiments are good in both the Raman and THz spectra in terms of spectral shapes, frequencies, and intensities. A Raman active band at 79 cm(-1) was assigned to the intermolecular vibrational mode of the out-of-plane C═O + CH(3) vibration. A polarization state of the corresponding far-infrared absorption band at ∼82 cm(-1), perpendicular to the helix-elongation direction of PHB, was reproduced only under the explicit correction, which indicates that this polarized band originates from the interaction among the polymer chains. The calculation explored that the polarization direction of this band was along the a axis, which is consistent with the direction in which weak intermolecular hydrogen bonds are suggested between the C═O and CH(3) groups of two parallel polymer chains. The results obtained here have confirmed sensitivity of the low-frequency vibrational bands to the weak hydrogen bonds among the polymer chains.

UV region'' is no longer appropriate for the 120-200 nm region because most recent spectrometers used in this region are not evacuated but instead incorporate a nitrogen purge. This review consists of eight parts: (1) introduction to FUV spectroscopy, (2) brief history of FUV spectroscopy, (3) development of new FUV spectrometers, (4) FUV studies of liquid water and aqueous solutions, (5) FUV spectra of organic molecules in the liquid states, (6) band assignments by quantum chemical calculations, (7) potential applications of FUV spectroscopy in liquid and solid states; and (8) future prospects of FUV spectroscopy.