Near Infrared Raman Spectroscopy

Wang C, Mohney B K, Williams R, Hupp J T and Walker G C 1998 Solvent control of vibronic coupling upon intervalence charge transfer excitation of (NC)gFeCNRu(NH3)g- as revealed by resonance Raman and near-infrared absorption spectroscopies J. Am. Chem. Soc. 120 5848-9... 

Near-infrared surface-enhanced Raman spectroscopy Some of the major irritants in Raman measurements are sample fluorescence and photochemistry. However, with the help of Fourier transform (FT) Raman instruments, near-infrared (near-IR) Raman spectroscopy has become an excellent technique for eliminating sample fluorescence and photochemistry in Raman measurements. As demonstrated recently, the range of near-IR Raman techniques can be extended to include near-IR SERS. Near-IR SERS reduces the magnitude of the fluorescence problem because near-IR excitation eliminates most sources of luminescence. Potential applications of near-IR SERS are in environmental monitoring and ultrasensitive detection of highly luminescent molecules [11]. 

A control technique based on high-frequency pressure measurements was developed and implemented to avoid hydrodynamic instabilities in continuous olefin slurry-loop reactors [ 186]. The obtained high-frequency pressure patterns are compared to typical process responses and then used to classify the status of the plant operation. The idea is that pressure fluctuations that do not follow the standard pattern indicate some sort of process instabiUty. When hydrodynamic instabilities are detected, monomer flow rates and/or reactor temperatures are manipulated to reduce the polymer density and the reaction rates and reduce the risks of plant shutdown. Similar procedures can be used for detection and correction of abnormal plant operation in suspension [ 187] and emulsion [188] polymerizations with the help of Raman and near infrared spectroscopy techniques. 

Fourier Transform Infrared Spectroscopy, Near Infrared Fourier and Transform Raman Spectroscopy Applied Photophysics Ltd. EDT Research Ltd. Foss Tecator JEOL Ltd. Perkin Elmer Corporation Philips Analytical Varian Instruments... 

M. Otsuka, R. Kato, and Y. Matsuda, Quantifying Ternary Mixtures of Different Solid-State Rorms of Indomethacin by Raman and Near-Infrared Spectroscopy, AAPS PharmSciTech, 2,1 (2000). 

Recently, other vibrational techniques have been used in the charactmza-tion of LDHs and the decomposition process, such as near-infrared spectroscopy (4000-8000 cm i) (311), Raman spectroscopy, and infrared emission spectroscopy (312,313). These new techniques offer more ways to investigate the structure and properties of LDHs. 

A. Matsushita, Y. Ren, K. Matsukawa, H. Inoue, Y. Minami, I. Noda, Y. Ozaki. Two-dimensional Fourier-transform Raman and near-infrared correlation spectroscopy studies of poly (methyl methacrylate) blends. 1. Immiscible blends of poly (methyl methacrylate) and atactic polystyrene. Vib Spectmsc 24 171, 2000. 

Fourier-transform Infrared Spectroscopy, Near Infrared Fourier and Transform Raman Spectroscopy... 

Fourier transform infrared spectroscopy, near infrared Fourier and transform Raman spectroscopy Mattson Instruments Ltd. Perkin Elmer Corp. Varian Instruments Philips Electronic Instruments Eoss Electronic JEOL Ltd. Applied Photophysics EDT Research... 

Itkis and his coworkers have recently compared different characterization methods, i.e., scanning electron microscopy [SEM], TEM, thermogravimetry (TGA], Raman, and near infrared [NIR] spectroscopy, in order to determine the optimum combination of these techniques to get reliable and accurate information about the purity of the CNT studied. They conclude that the combination of TGA and Raman spectroscopy is quite satisfying. In the same field, Herrera et al. reported a successful use of in situ temperature programmed oxidation [TPO] and Raman spectroscopy to reach the same goal. 

Continuous wave (CW) lasers such as Ar and He-Ne are employed in conmionplace Raman spectrometers. However laser sources for Raman spectroscopy now extend from the edge of the vacuum UV to the near infrared. Lasers serve as an energetic source which at the same hme can be highly monochromatic, thus effectively supplying the single excitation frequency, v. The beams have a small diameter which may be... 

Lasers having wavelengths ranging from the deep uv to the near infrared have been used in Raman spectroscopy. In industrial laboratories, the most common laser is the Nd YAG operating at 1.06 pm. Increasingly, diode lasers or other lasers operating in the 750—785-nm region are encountered. These... 

For the visible and near-ultraviolet portions of the spectmm, tunable dye lasers have commonly been used as the light source, although they are being replaced in many appHcation by tunable soHd-state lasers, eg, titanium-doped sapphire. Optical parametric oscillators are also developing as useful spectroscopic sources. In the infrared, tunable laser semiconductor diodes have been employed. The tunable diode lasers which contain lead salts have been employed for remote monitoring of poUutant species. Needs for infrared spectroscopy provide an impetus for continued development of tunable infrared lasers (see Infrared technology and RAMAN spectroscopy). 

Materials characterization techniques, ie, atomic and molecular identification and analysis, ate discussed ia articles the tides of which, for the most part, are descriptive of the analytical method. For example, both iaftared (it) and near iaftared analysis (nira) are described ia Infrared and raman SPECTROSCOPY. Nucleai magaetic resoaance (nmr) and electron spia resonance (esr) are discussed ia Magnetic spin resonance. Ultraviolet (uv) and visible (vis), absorption and emission, as well as Raman spectroscopy, circular dichroism (cd), etc are discussed ia Spectroscopy (see also Chemiluminescence Electho-analytical techniques It unoassay Mass specthot thy Microscopy Microwave technology Plasma technology and X-ray technology). 

Infrared Spectrophotometry. The isotope effect on the vibrational spectmm of D2O makes infrared spectrophotometry the method of choice for deuterium analysis. It is as rapid as mass spectrometry, does not suffer from memory effects, and requites less expensive laboratory equipment. Measurement at either the O—H fundamental vibration at 2.94 p.m (O—H) or 3.82 p.m (O—D) can be used. This method is equally appticable to low concentrations of D2O in H2O, or the reverse (86,87). Absorption in the near infrared can also be used (88,89) and this procedure is particularly useful (see Infrared and raman spectroscopy Spectroscopy). The D/H ratio in the nonexchangeable positions in organic compounds can be determined by a combination of exchange and spectrophotometric methods (90). 

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