IR, Raman 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.

Knowledge of the stracture and bonding of molecnles to snrfaces has been obtained from such techniques as LEED, electron energy-loss spectroscopy (EELS), secondaiy-ion mass spectrometry (SIMS), infrared spectroscopy (IRS), Raman spectroscopy, and NMR spectrometiy. The scope of snch studies needs to be greatly expanded to include the effects of coadsorbates, promoters, and poisons. Greater emphasis should be given to developing new photon spectroscopies that would permit observation of adsorbed species in the presence of a gas... 

Me2SnF4]2-[NH4]+2 Mossbauer and IR, Raman spectroscopy. The methyl groups are trans to each other. Normal N—H- F hydrogen bonds. 153... 

Another polymer symposia was organised by IUPAC in 1947 in Liege. At this conference, the discussion included synthesis and technology of polymers like polyethylene, nylon, polyester. New characterisation methods such as x-ray scattering, x-rays, electron microscope, osmometry, nmr, IR, Raman spectroscopy, etc. were now available for characterisation of polymers. These methods become essential because of increasing complexity of new polymers. 

A spectroscopic study of Claus blue, with comparisons to the much better characterized (180) ion [Rh2(0H)2(H20)n(/u,-02)]3+, was thus undertaken (181). By the use of UV-vis, ESR, and IR/Raman spectroscopies, as well as magnetic susceptibility measurements and voltamme-tric studies, it was determined that Claus blue solutions actually contain superoxo-dirhodium complexes, and not RhO2- ions. The su-peroxo bridge does not, however, derive from dioxygen, but from oxidation of coordinated hydroxide. Finally, Claus blue solutions were demonstrated to be good starting materials for the preparation of superoxo-dirhodium carboxylate complexes, which could be isolated and characterized. 

The H3NAIX3 molecules have been studied in the gas phase by IR/Raman spectroscopy.24 NCA yields Al—N force constants of 1.50N cm-1 (X = C1) and 1.45 N cm-1 (X = Br). The analyses of spectra were supported by ab initio MO calculations which were also extended to H3NAIF3, a molecule which has eluded synthesis. The ammonia adduct of alane (A1H3) is unknown. A hexaammine A1(BH4)3-6NH3 is the product of excess ammonia on KA1(BH4)4.25 It is believed to contain the cation A1(NH3)1+ and it is possible that this species is also present in some of the complexes A1X3(NH3) , noted above, but structural investigation is required. 

Ryder, A.G., O Connor, G.M. and Glynn, T.J. (1999) Identifications and quantitative measurements of narcotics in solid mixtures using near-IR Raman spectroscopy and multivariate analysis /. Forensic Sci. 44, 1013-1019. 

Physical Form X-ray Powder Diffraction LOD LOQ (%) Solid-State NMR Spectroscopy LOD LOQ (%) IR/Raman Spectroscopy LOD LOQ (%)... 

Among a variety of spectroscopic methods, vibrational spectroscopy is most commonly used in structural chemistry. IR/Raman spectroscopy provides information about molecular symmetry of relatively small molecules and functional groups in large and complex molecules. Furthermore, Raman spectroscopy enables us to study the structures of electronically excited molecules and unstable species produced by laser photolysis at low temperatures. Several other applications that are important in structural chemistry are also discussed in this section. 

Vibrational Energy Redistribution in Polyatomic Liquids Ultrafast IR-Raman Spectroscopy... 

Deak JC, Iwaki LK, Dlott DD. Vibrational energy redistribution in polyatomic liquids ultrafast IR-Raman spectroscopy of nitromethane. J Phys Chem A 103 971-979. 

The intermediates which play a role in a cycle of a homogeneous catalyst can be characterized by various spectroscopic techniques such as NMR, IR, Raman spectroscopy, and UV-vis spectroscopy. Also, intermediates may crystallize from a reaction mixture and the structure can then be solved with a single-crystal X-ray determination. Only on rare occasions do intermediates crystallize from the... 

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]. 

Thus for X = F studies using and IR Raman spectroscopy " indicated... 

Near-IR Raman spectroscopy was used by Mehadevan-Jansen et al. [159] to differentiate cervical precancers from healthy or normal tissue. The algorithms generated may potentially separate benign abnormalities such as inflammation and metaplasia from precancers. 

The intermediates which play a role in a cycle of a homogeneous catcilyst can be characterized by various spectroscopic techniques such as NMR, IR, Raman spectroscopy, and UV-vis spectroscopy. Also, intermediates may crystallize from a reaction mixture and the structure can then be solved with a single-crystal X-ray determination. Only on rare occasions do intermediates crystallize from the reacting systems since their concentrations are low. Often one turns to model compounds of the actual catalyst by changing the ligand or the metal. For example, iridium complexes show the same catalytic behaviour as the rhodium complexes. Since they are often much slower as catalysts the intermediates can be intercepted (see below). Another common approach is the synthesis of a ligand that simultaneously contains the substrate of the catalytic reaction this may also lead to the isolation of likely intermediates. 

REACTION CONDITIONS XRO, TP techniques, IR, Raman spectroscopy, EXAFS, Mdssbauer spectroscopy, ESR, NMR IR, TP techniques... 

Since the objective of the studies described herein is the characterisation of the solute species formed following redox reaction the very extensive research dealing with characterisation of the electrode/solute interface will not be discussed, excellent overviews of the experimental aspects of this subject are available. While this contribution focuses on applications involving IR, Raman spectroscopy has proved to be invaluable to many SEC studies where surface-enhanced Raman spectroscopy (SERS) and resonance Raman spectroscopy dominate. Reviews and recent studies attest to the value of these approaches. ... 

A combination of IR and Raman spectroscopy has confirmed that the ring atoms and substituents in 2-amino-4-methoxy-6-methyl-l,3,5-triazine are exactly planar . IR/Raman spectroscopy was applied to triazinyl peroxides (see Section 6.12.5.1.4) and the results were analyzed by a frequency calculation model due to Bleckman <74ZN(A)1485>. 

The decay of C-H stretching (and OH and NH) vibrations in liquids has been studied by IR-Raman spectroscopy... 

Multinuclear NMR- C C, Pt, ° T1), IR-, Raman-spectroscopy. Electron Spectroscopy for Chemical Analysis (ESCA), X-ray, and Extended X-ray Absorption Fine Structure (EXAFS) studies confirm direct, short (2.60-2.64 A) Pt-Tl bonds. Figure 1. shows a typical Tl NMR spectrum of [(N C)5Pt-Tl( CN)] together with the structure determined by EXAFS. The spin-spin coupling pattern is consistent with 4 +1-1-1 equivalent ligands (I = 1/2),... 

Urban FTIR ir Raman Spectroscopy of Water-Soluble Polymers... 

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