Raman spectrophotometer

These frequencies are low in the spectrum and inaccessible to our spectrophotometer. Raman spectra cover this range but their resolution is poor close to the exciting line. Thus, our approach takes provisional account of the frequencies observed by Mathieu <3cPtc (Bsp) =95 cm i and CPdc (B2ff) =94 cm i. 

UV diffuse reflectance spectra of the titanates were obtained with a JASCO UVIDEC-660 spectrophotometer using a sintered alumina disc as a reference. Raman spectra were recorded at room temperature on a JASCO NR-1100 spectrometer. 

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). 

For a fluorescence detector, quinine sulfate is used as the standard compound. The flow cell is filled with a standard solution and the fluorescence intensity is measured. The value is compared with that measured by a fluorescence spectrophotometer. This standard solution is also used for fixing the wavelength and position of the flow cell. The Raman spectrum of water can also be used for this purpose. 

We have seen in the previous section that Raman spectra are complementary to infrared spectra. Both spectroscopies provide quite useful information on the phonon structure of solids. However, infrared spectra correspond to a range from about 100 cm to about 5000 cm that is, far away from the optical range. Thus, infrared absorption spectra are generally measured by so-called Fourier Transform InfraRed (FTIR) spectrometers. These spectrometers work in a quite different way to the absorption spectrophotometers discussed in Section 1.3. 

M.J. Pelletier, New developments in analytical instruments Raman scattering emission spectrophotometers, in Process/Industrial Instruments and Controls Handbook, G.K. McMillan and D.M. Considine (Eds), McGraw-Hill, New York, 1999. 

Raman spectra were taken on a home built system, composed of Spectra-Physics 2020 series lasers, coupled with a Dilor XY-800 triple spectrometer and a Whight Instruments nitrogen cooled CCD. All samples were measured at room temperature in a backscattering configuration, with 514.53 nm Ar+ laser excitation. The laser power was tuned between 1 mW and 30 mW. UV-VIS diffuse reflectance spectra were taken on a Varian Cary 5 spectrophotometer, equipped with a specially designed Praying Mantis diffuse reflectance attachment of Harrick. 

Since the article by Spedding1 on infrared spectroscopy and carbohydrate chemistry was published in this Series in 1964, important advances in both infrared and Raman spectroscopy have been achieved. The discovery2 of the fast Fourier transform (f.F.t.) algorithm in 1965 revitalized the field of infrared spectroscopy. The use of the f.F.t., and the introduction of efficient minicomputers, permitted the development of a new generation of infrared instruments called Fourier-transform infrared (F.t.-i.r.) spectrophotometers. The development of F.t.-i.r. spectroscopy resulted in the setting up of the software necessary to undertake signal averaging, and perform the mathematical manipulation of the spectral data in order to extract the maximum of information from the spectra.3... 

Pelletier, M.J. New Developments in Analytical Instruments Raman Scattering Emission Spectrophotometers. In McMillan, G.K. Considine, D.M. (eds) Process/Industrial Instruments and Controls Handbook 5th Edition McGraw-Hill New York, 1999 pp. 10.126-10.132. 

Variable-temperature laser Raman spectra between 15 and 70 K were measured for a polycrystalline sample mounted in an Oxford CF1204 cryostat using a Jasco NR-1800 Raman spectrophotometer. 

Spectroscopic Measurements. A Beckman Model 5230 spectrophotometer was used to record in situ UV-visible spectra of the PPy films, which were electrochemically deposited on the indium-tin oxide (ITO) coated glass (Delta Technologies). For Raman measurements a Spex Model 1403 double spectrometer, a DM IB Datamate, and a Houston Instrument DMP-40 digital plotter were employed. Details of the experimental setup for in situ Raman spectroscopy are described elsewhere (26). 

The state of the art Raman system costs much more than a conventional FT-IR spectrophotometer although less expensive versions have appeared which are smaller and portable and suitable for process applications (Section 2-10). 

If additional accuracy is desired (on the order of 0.5 cm-1), then indene may be used (20). Indene also has been used as a frequency calibrant for IR spectrophotometers. Before use, it should be purified by vacuum distillation and stored in sealed capillary or an NMR tube. Figure 2-13 shows the Raman spectrum of indene, and Table 2-7 lists the frequencies that are recommended for use in calibration. 

For SERS measurements on condensed-phase interfaces, a conventional Raman spectrophotometer can be used. The laser beam in the visible or... 

Pressed pellets of BaTiC>3 were sintered in a platinum dish for six hours at 900°C in a controlled partial pressure of oxygen. The samples were quenched to room temperature, and the spectra recorded on a four-slit double-monochromator Raman spectrophotometer. An Ar+ laser with excitation at 514.5 nm was the source. The spectra were recorded at room temperature. Figure 4-30 shows the spectrum of BaTiC>3 whose Ba/Ti ratio is equal to 0.9999. The Raman spectrum is sensitive to the Ba/Ti ratio and theoxygen non-stoichiometry. The half-band width is variable as well as the intensity ratio of the 525 and 713 cm-1 bands. The ratio (I525/713) is at a minimum at the composition of 0.9999, and this can be observed in Fig. 4-31, which shows a plot of the intensity ratio (I525//713) vs. the Ba/Ti composition. 

Measurements. The absorption, circular dichroism (CD), and ESR spectra were recorded with a Hitachi 323 spectrophotometer, a JASCO MOE-1 magnetic circular dichroism spectrometer, and a JEOL JES-FE3X ESR spectrometer, respectively. The measurements of the spectra were carried out at 15°-20°C except for the ESR spectra, which were recorded at 77 K. The resonance Raman spectra were recorded at 10°C with 488.0-nm excitation (Ar+ laser) on a JEOL JRS-400D-002 spectrophotometer. The concentration of copper was determined to be 4.9mM by atomic absorption measured by a Nippon Jarrell-Ash AA-1 spectrometer. 

Auxiliary Instruments. Auxiliary instruments can be used on the fly as special detectors, or analytes can be trapped and taken to other instruments. Instruments that have been used with chromatography include the mass spectrometer (MS), the infrared spectrometer (IR), the nuclear magnetic resonance spectrometer (NMR), the polarograph, the fluorescence spectrophotometer, and the Raman spectrometer, among others. The two most popular ones are MS and IR, and they will be discussed in more detail in Chapter 11. In the beginning of this chapter we noted the utility iof GC/MS and LC/MS. 

T4. Thomas, G. J., and Barylski, J. R., (Jacket for) thermostating capillary cells for a laser-Raman spectrophotometer. Appl. Spectrosc. 24, 463-464 (1970). 

The single crystal of gas hydrate prepared from H2 + CO2 and H2 + CO2 + THF mixtures was analyzed by in situ Raman spectroscopy using a laser Raman microprobe spectrophotometer with multichannel CCD detector. In the present study, the single crystal was defined as the gas hydrate crystal for which the Raman peak of the intermolecular 0-0 vibration mode can be detected. The argon ion laser beam (wavelength 514.5 nm, power 100 mW) or He-Ne laser beam (wavelength 632.8 nm, power 35 mW) condensed to 2 pm in spot diameter was irradiated to the sample through the upper sapphire (or quartz) window. The backscatter of the opposite direction was taken in with the same lens. The spectral resolution was about 1 cm ... 

Figure 5 FT-Raman spectrum of native aminoethyl TentaGel S beads (lower curve) and of TentaGel S beads coupled via a trityl linker with Fmoc-protected tryptophan (upper curve). The spectra were obtained with 300 scans at 4 cm 1 resolution by means of a Bruker IFS 55/S spectrophotometer equipped with a Bruker FRA 106 FT-Raman accessory. For excitation, a Nd YAG laser working at 1064 nm was used with a power of 390 mW.

The 488.0 nm Coherent Radiation Model 520-B argon-ion laser of 300 mW power was focused on the center of the drop and the Raman light is detected perpendicular to both the laser beam and the sample tube. Qualitative polarization measurements were made by rotating the plane of polarization of the laser beam with a half-wave plate. In most of the spectra, it was not necessary to use a spike filter to attenuate the plasma lines. The spectra were recorded using a modified Cary 81 spectrophotometer employing a 9558A EMI photo-multiplier counting detection system. 

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