Optical Raman spectroscopy

Angel, S.M., and M.L. Myrick. 1990. Wavelength selection for fiber optic Raman spectroscopy. Applied Optics 29 1350-1352. 

Among the advanced techniques employed to follow the cure reaction, Fiber Optic Raman Spectroscopy has been an effective tool. By this technique, both the temperature build-up and the cure advancement of AroCy L-10 could simultaneously be followed. The local temperature of the sample, determined by Ra-man-Stokes and anti-Stokes scattering of a reference peak correlated well with the temperature measured using a thermocouple probe. The extent of cure could be monitored using either individual peaks associated with the reactant or product or by using the entire spectrum [104]. 

Table 1 compares the nonfocusing and the focusing fiber optic Raman probes. Both styles of probe have unique and important roles to play in fiber optic Raman spectroscopy. 

Figure 2 A normal Raman spectrum of acid black 1 at low-ppm concentrations taken at short analysis times. (Reprinted with permission from DA Gilmore, D Gurka, MB Denton. Quantitative detection of environmentally important dyes using diode laser/fiber optic Raman spectroscopy. Appl Spectrosc 49 508-512, 1995. Copyright 1995 Society for Applied Spectroscopy.)...

DA Gilmore, D Gurka, MB Denton. Quantitative detection of environmentally important dyes using diode laser/fiber optic Raman spectroscopy. Appl Spectrosc 49 508-512, 1995. 

A Al-Khanbashi, M Dhamdhere, M Hansen. Application of in-line fiber-optic Raman spectroscopy to monitoring emulsion polymerization reactions. Appl Spectrosc Rev 33 115-131, 1998. 

C Wang, TJ Vickers, JB Schlenoff, C Mann. In-situ monitoring of emulsion polymerization using fiber-optic Raman spectroscopy. Appl Spectrosc 46 1729-1736, 1992. 

Raman spectroscopy has also been applied as a rapid characterisation tool of ex-reactor aliphatic polyketones. Chalmers et al. [104] have described off-line compositional analysis by means of Raman and FT-Raman of EO-PO copolymers (non-ionic surfactants) for QA/QC purposes PLS modelling can importantly decouple the spectral influences of crystallinity and orientation on Raman spectra. Simultaneous monitoring of composition and rheological properties of EVA copolymers by means of inline fibre-optic Raman spectroscopy was reported [188,189],... 

Esmonde-White, K.A. et al. (2011) Fiber-optic Raman spectroscopy of joint tissues. Analyst, 136 (8), 1675-1685. 

Transcutaneous fiber optic Raman spectroscopy of bone using annular illumination and a circular array of collection fibers. J. Biomed. Opt, 11 (6), 060502. 

In-line monitoring of EVA extrusion was carried out using in-line fibre optic Raman spectroscopy. Vinyl acetate content in the random copolymer and melt indices of various grades of the EVA were determined and vinyl acetate content in the samples correlated using linear least squares andPLS analysis. Hierarchical Cluster analysis was employed as a pattern recognition technique to follow the natural clustering tendencies of the EVA samples. 10 refs. 

The 70 years since these first observations have witnessed dramatic developments in Raman spectroscopy, particularly with the advent of lasers. By now, a large variety of Raman spectroscopies have appeared, each with its own acronym. They all share the conunon trait of using high energy ( optical ) light to probe small energy level spacings in matter. 

The unique feature in spontaneous Raman spectroscopy (SR) is that field 2 is not an incident field but (at room temperature and at optical frequencies) it is resonantly drawn into action from the zero-point field of the ubiquitous blackbody (bb) radiation. Its active frequency is spontaneously selected (from the infinite colours available in the blackbody) by the resonance with the Raman transition at co - 0I2 r material. The effective bb field mtensity may be obtained from its energy density per unit circular frequency, the... 

Barron L D, Hecht L, Bell A F and WIson G 1996 Raman optical activity an incisive probe of chirality and biomolecular structure and dynamics ICORS 96 XVth Int. Conf. on Raman Spectroscopy ed S A Asher and P B Stein (New York Wley) pp 1212-15... 

Hecht L and Barron L D 1996 Raman optical activity Modern Techniques in Raman Spectroscopy ed J J Laserna (New York Wley) pp 265-342... 

Tsai D P, Othonos A, Moskovits M and Uttamchandani D 1994 Raman spectroscopy using a fibre optic probe with subwavelength aperture Appl. Phys. Lett. 64 1768... 

Smith D A, Webster S, Ayad M, Evans S D, Fogherty D and Batchelder D 1995 Development of a scanning near-field optical probe for localised Raman spectroscopy Ultramicroscopy 61 247... 

Perhaps the best known and most used optical spectroscopy which relies on the use of lasers is Raman spectroscopy. Because Raman spectroscopy is based on the inelastic scattering of photons, the signals are usually weak, and are often masked by fluorescence and/or Rayleigh scattering processes. The interest in usmg Raman for the vibrational characterization of surfaces arises from the fact that the teclmique can be used in situ under non-vacuum enviromnents, and also because it follows selection rules that complement those of IR spectroscopy. 

Figure C3.5.3. Schematic diagram of apparatus used for (a) IR pump-probe or vibrational echo spectroscopy by Payer and co-workers [50] and (b) IR-Raman spectroscopy by Dlott and co-workers [39]. Key OPA = optical parametric amplifier PEL = free-electron laser MOD = high speed optical modulator PMT = photomultiplier OMA = optical multichannel analyser.

ALCOHOLS,HIGHERALIPHATIC - SURVEY AND NATURALALCOHOLSMANUFACTURE] (Voll) -analysis using Raman spectroscopy [SPECTROSCOPY, OPTICAL] (Vol 22)... 

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