FT-Raman

Nonnal spontaneous Raman scahering suffers from lack of frequency precision and thus good spectral subtractions are not possible. Another limitation to this technique is that high resolution experiments are often difficult to perfomi [39]. These shortcomings have been circumvented by the development of Fourier transfomi (FT) Raman spectroscopy [40]. FT Raman spectroscopy employs a long wavelength laser to achieve viable interferometry. 

Other than the obvious advantages of reduced fluorescence and high resolution, FT Raman is fast, safe and requires mmimal skill, making it a popular analytic tool for the characterization of organic compounds, polymers, inorganic materials and surfaces and has been employed in many biological applications [41]. 

RDOs is much smaller than that for the vibration itself, not to mention that for the near-IR FT-Raman teclmique already discussed. This is particularly striking for high energy modes such as the C-H vibrations [108]. Modem applications of I CRS now utilize a two-dimensional time-frequency detection scheme... 

Hirschfeld T and Chase B 1986 FT-Raman spectroscopy development and justification Appl. Spectrosc. 40 133-9... 

The infrared laser which is mosf often used in this technique of Fourier transform Raman, or FT-Raman, spectroscopy is the Nd-YAG laser (see Section 9.2.3) operating at a wavelength of 1064 nm. 

In FT-Raman spectroscopy the radiation emerging from the sample contains not only the Raman scattering but also the extremely intense laser radiation used to produce it. If this were allowed to contribute to the interferogram, before Fourier transformation, the corresponding cosine wave would overwhelm those due to the Raman scattering. To avoid this, a sharp cut-off (interference) filter is inserted after the sample cell to remove 1064 nm (and lower wavelength) radiation. 

An FT-Raman spectrometer is often simply an FTIR spectrometer adapted to accommodate the laser source, filters to remove the laser radiation and a variety of infrared detectors. 

More recently, Raman spectroscopy has been used to investigate the vibrational spectroscopy of polymer Hquid crystals (46) (see Liquid crystalline materials), the kinetics of polymerization (47) (see Kinetic measurements), synthetic polymers and mbbers (48), and stress and strain in fibers and composites (49) (see Composite materials). The relationship between Raman spectra and the stmcture of conjugated and conducting polymers has been reviewed (50,51). In addition, a general review of ft-Raman studies of polymers has been pubUshed (52). 

Friedel-Crafts catalysts, 329, 331 Friedel-Crafts reaction, 297, 361 Front-end reactions, 235 FT Raman spectroscopy, 387 FTIR spectrometry. See Fourier transform infrared (FTIR) spectrometry Fuel cells, 272-273 Full prepolymers, 236, 237 Functionalized polyolefins, 459-460... 

Spectroscopy, 490. See also 13C NMR spectroscopy FT Raman spectroscopy Fourier transform infrared (FTIR) spectrometry H NMR spectroscopy Infrared (IR) spectroscopy Nuclear magnetic resonance (NMR) spectroscopy Positron annihilation lifetime spectroscopy (PALS) Positron annihilation spectroscopy (PAS) Raman spectroscopy Small-angle x-ray spectroscopy (SAXS) Ultraviolet spectroscopy Wide-angle x-ray spectroscopy (WAXS)... 

Fig. 5. FT-Raman spo of (a) the raw SWNTs sample and (b) the purifi sample Ni, Co and FeS were used as a catalysts)...

Schulz, H., Baranska, M., and Baranski, R., Potential of NIR-FT-Raman spectroscopy in natural carotenoid analysis. Biopolymers, 11, 212, 2005. 

Baranska, M. et al.. Identification of secondary metabolites in medicinal and spice plants by NIR FT Raman microspectroscopic mapping. Analyst, 129, 926, 2004. 

The sensitivity limitations of TLC-FT-Raman spectroscopy may be overcome by applying the SERS effect [782]. Unlike infrared, a major gain in Raman signal can be achieved by utilising surface activation and/or resonance effects. Surface-enhanced Raman (SER) spectra can be observed for compounds adsorbed on (rough) metahic surfaces, usually silver or gold colloids [783,784], while resonance Raman (RR) spectra... 

Since SERS and SERRS are substance specific, they are ideal for characterisation and identification of chromatographically separated compounds. SE(R)R is not, unfortunately, as generally applicable as MS or FUR, because the method requires silver sol adsorption, which is strongly analyte-dependent. SE(R)R should, moreover, be considered as a qualitative rather than a quantitative technique, because the absolute activity of the silver sol is batch dependent and the signal intensity within a TLC spot is inhomogeneously distributed. TLC-FTIR and TLC-RS are considered to be more generally applicable methods, but much less sensitive than TLC-FT-SERS FT-Raman offers p,m resolution levels, as compared to about 10p,m for FTIR. TLC-Raman has been reviewed [721],... 

TLC-Raman laser microscopy (X = 514 nm) in conjunction with other techniques (IR microscopy, XRF and HPLC-DAD-ESI-MS) has been used in the analysis of a yellow impurity in styrene attributed to reaction of the polymerisation inhibitor r-butylcatechol (TBC) and ammonia (from a washing step) [795]. Although TLC-FT-Raman did not allow full structural characterisation, several structural elements were identified. Exact mass measurement indicated a C20H25O3N compound which was further structurally characterised by 1H and 13C NMR. 

A rapid characterization of the viscosity of waterborne automotive paint was reported by Ito et al. [24], FT-Raman spectroscopy in conjunction with partial least squares regression (PLS) was applied and led to a reasonable correlation. 

SGW wish to thank, IIT Bombay for providing FT Raman and Technical University Graz for providing X-ray Rietveld refinement of Nal and Agl-SOD. 

Samples were characterized by FTIR spectroscopy with a Perkin Elmer (Spectrum BX) spectrometer using KBr pressed disks as matrices. The DRIFT experiments were carried out with a Broker IFS 55 spectrometer equipped with a Thermo Spectra Tech reacting cell. UV-vis Diffuse Reflectance spectra were recorded on a Perkin Elmer Lambda 45 spectrophotometer equipped with a diffuse reflectance attachment. Raman spectra were collected with Perkin Elmer system 2000 NIR FT-Raman using as excitation radiation the 5th harmonic of a diode pumped Nd YAG laser (1065 nm). 

Keywords AlP04-5, hydrothermal synthesis, organic template, FT-Raman, XRD. 

---