Detection spectroscopy

Temperature monitoring of proton-decoupled C-detected spectroscopy experiments in monkey brain showed that a WALTZ-4 decoupling scheme with... 

The second-order rate constant of the cleavage of PNPA with this polymer, D( 10%)-PEI-Im(15%) (10% dodecyl group, 15% methyleneimidazole group) 7 was 45 M sec at pH 7.3,25° C on the baas of methyleneimidazole group a value more than 100 times as effective as imidazole itself. The catalysis includes formation and decomposition of acetylimidazole intermediate, and the latter rate was estimated to be (1—6) X 10 sec 10 times greater than that of simple acetylimidazole under the same condition. The formation of acetylimidazole unit was detected spectroscopi-caHy(727). 

Zijlstra, P., Orrit, M., 2011. Single metal nanoparticles optical detection, spectroscopy and applications. Rep. Prog. Phys. 74 (10), 106401. 

G. Stella, J. Gelfand, W.H. Smith, Photoacoustic detection spectroscopy with dye laser excitation. The 6190 A CH4 and the 6450 NHs-bands. Chem. Phys. Lett. 39, 146 (1976)... 

Radiation detectors have played and continue to play an essential role in the study and use of nuclear transformations. The goal of this chapter is to describe the general characteristics of radiation detectors with emphasis on detectors for radiations associated with radioactive decay. These radiations include photons, electrons (both negative and positive), and energetic atomic ions (primarily, but not exclusively, aparticles). The detectors can be classed according to the physical form of the detector (gas, liquid, sohd), the nature of the signal (ions, current, light), or the purpose (simple detection, spectroscopy, or diverse other roles). 

E. Harel, Magnetic Resonance Detection Spectroscopy and Imaging of Lab-on-a-Chip , Lab Chip, 2009, 9, 17. 

Analytical Chemistry DNA ItesTiNG in Forensic Science Environmental Toxicology Mass Spectrometry IN Forensic Science Organic Chemistry, Compound Detection Spectroscopy in Forensic Science... 

J Storey, T Barber, B Shelton, E Wachter, K Carron, Y Jiang. Applications of surface enhanced Raman scattering (SERS) to chemical detection. Spectroscopy 10 20-25, 1995. 

The availability of large volume LaBrs Ce detectors has generated in the scientific community working with scintillators a large interest as its properties make it the best scintillator crystal for gamma detection/spectroscopy and, a possible alternative to HPGe. 

X-ray spectroscopy Analytical method by which a sample is irradiated with X-rays, characteristic radiation being emitted after scattering from the specimen. The detection limits for various elements are of the ordering cm. ... 

Electron Spin Resonance Spectroscopy. Several ESR studies have been reported for adsorption systems [85-90]. ESR signals are strong enough to allow the detection of quite small amounts of unpaired electrons, and the shape of the signal can, in the case of adsorbed transition metal ions, give an indication of the geometry of the adsorption site. Ref. 91 provides a contemporary example of the use of ESR and of electron spin echo modulation (ESEM) to locate the environment of Cu(II) relative to in a microporous aluminophosphate molecular sieve. 

Electronic spectra of surfaces can give information about what species are present and their valence states. X-ray photoelectron spectroscopy (XPS) and its variant, ESC A, are commonly used. Figure VIII-11 shows the application to an A1 surface and Fig. XVIII-6, to the more complicated case of Mo supported on TiOi [37] Fig. XVIII-7 shows the detection of photochemically produced Br atoms on Pt(lll) [38]. Other spectroscopies that bear on the chemical state of adsorbed species include (see Table VIII-1) photoelectron spectroscopy (PES) [39-41], angle resolved PES or ARPES [42], and Auger electron spectroscopy (AES) [43-47]. Spectroscopic detection of adsorbed hydrogen is difficult, and... 

Scherer N F, Carlson R J, Matro A, Du M, Ruggiero A J, Romero-Rochin V, Cina J A, Fleming G R and Rice S A 1991 Fluorescence-detected wave packet interferometry time resolved molecular spectroscopy with sequences of femtosecond phase-locked pulses J. Chem. Rhys. 95 1487... 

While a laser beam can be used for traditional absorption spectroscopy by measuring / and 7q, the strength of laser spectroscopy lies in more specialized experiments which often do not lend themselves to such measurements. Other techniques are connnonly used to detect the absorption of light from the laser beam. A coimnon one is to observe fluorescence excited by the laser. The total fluorescence produced is nonnally proportional to the amount of light absorbed. It can be used as a measurement of concentration to detect species present in extremely small amounts. Or a measurement of the fluorescence intensity as the laser frequency is scaimed can give an absorption spectrum. This may allow much higher resolution than is easily obtained with a traditional absorption spectrometer. In other experiments the fluorescence may be dispersed and its spectrum detennined with a traditional spectrometer. In suitable cases this could be the emission from a single electronic-vibrational-rotational level of a molecule and the experimenter can study how the spectrum varies with level. 

The interpretation of emission spectra is somewhat different but similar to that of absorption spectra. The intensity observed m a typical emission spectrum is a complicated fiinction of the excitation conditions which detennine the number of excited states produced, quenching processes which compete with emission, and the efficiency of the detection system. The quantities of theoretical interest which replace the integrated intensity of absorption spectroscopy are the rate constant for spontaneous emission and the related excited-state lifetime. 

As noted, the Class II spectroscopies are based on detecting the new EM field that is derived from the induced... 

Clip acts in phase (the same Fourier component) with the first action of cii to produce a polarization that is anti-Stokes shifted from oi (see fV (E) and IFj (F) of figure B 1.3.2(b)). For the case of CSRS the third field action has frequency CO2 and acts in phase with the earlier action of CO2 (W (C) and IFj (D) of figure Bl.3.2 (b). Unlike the Class I spectroscopies, no fields in CARS or CSRS (or any homodyne detected Class II spectroscopies) are in quadrature at the polarization level. Since homodyne detected CRS is governed by the modulus square of hs lineshape is not a synmretric lineshape like those in the Class I... 

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