A spectroscopic techniques

EXAFS Extended X-ray absorption fine structure spectroscopy. A spectroscopic technique which can determine interatomic distances very precisely. 

Nuclear magnetic resonance, NMR (Chapter 13 introduction) A spectroscopic technique that provides information about the carbon-hydrogen framework of a molecule. NMR works by detecting the energy absorptions accompanying the transitions between nuclear spin states that occur when a molecule is placed in a strong magnetic field and irradiated with radiofrequency waves. 

Fourier transform infrared (FTIR) A spectroscopic technique of analysis based on the use of infrared radiation. 

It is a spectroscopic technique, hence the optical properties of the film can be probed over the entire spectral range of the instrument, typically UV to near-IR. 

The technique employed is IR-FT photothermal beam deflection spectroscopy (PBDS). It is an off-shoot of photoacoustic spectroscopy (PAS) [1] and is based on the "mirage detection of the photothermal effect invented by Boccara et al. [2] and shown to result in a spectroscopic technique of remarkable versatility and utility. Some applications of "mirage spectroscopy," mainly in the visible, and theoretical treatments, have been described [3 6]. The method has now been developed for use in the IR. The spectrometer and techniques are described in detail elsewhere [7], but it will be useful to give a brief outline of the principles. 

Most stable ground-state molecules contain closed-shell electron configurations with a completely filled valence shell in which all molecular orbitals are doubly occupied or empty. Radicals, on the other hand, have an odd number of electrons and are therefore paramagnetic species. Electron paramagnetic resonance (EPR), sometimes called electron spin resonance (ESR), is a spectroscopic technique used to study species with one or more unpaired electrons, such as those found in free radicals, triplets (in the solid phase) and some inorganic complexes of transition-metal ions. 

Fourier transform spectroscopy spect A spectroscopic technique in which all pertinent wavelengths simultaneously Irradiate the sample for a short period of time, and the absorption spectrum is found by mathematical manipulation of the Fourier transform so obtained. fur e a tranz,form spek tras-ko-pe fp See freezing point. 

A spectroscopic technique that measures the differential absorption of left and right circularly polarized hght as... 

A spectroscopic technique (often abbreviated FRAP) that relies on highly localized photobleaching within specific cell regions to detect and/or measure (a) the lateral diffusibility of molecules within membranes, (b) the diffusion and replacement of molecules within assembled structures, such as the cytoskeleton, and (c) related diffusion and exchange of substances within the cell s aqueous phases. The recovery (or redistribution) phase that follows the photobleaching event provides valuable infor-... 

A spectroscopic technique that is associated with the enhancement of Raman line intensities upon photon absorption in the electronic spectral range corresponding to an absorption peak. See Raman Spectroscopy... 

In order to study a physicochemical property of a dendritic molecule which does not involve either the creation of a cavity in the solvent or the change in its shape, we chose as representative a property that could be studied by a spectroscopic technique such as the molecular tumbling phenomena. Such phenomena occur both... 

Not really a spectroscopic technique in that the line spectrum produced does not arise from quantization of electromagnetic radiation. Of specialized interest only not further discussed here. 

The mole fraction solubilities of ten copper(II) and five chromium(III) P-diketo-nates were measured in SCCO2 with a spectroscopic technique and found to vary over four orders of magnitude. Observed trends indicate that the solubility in supercritical carbon dioxide is strongly dictated by the character of the hydrocarbon or fluorocarbon shell surrounding the central metal atom. A regular solutions approach was used for Cr(acac)°3 to quantitatively attempt to predict the solubility in SCCO2. Solubility... 

Principle Advantages and Disadvantages of ESCA as a Spectroscopic Technique... 

X-ray fluorescence is a spectroscopic technique of analysis, based on the fluorescence of atoms in the X-ray domain, to provide qualitative or quantitative information on the elemental composition of a sample. Excitation of the atoms is achieved by an X-ray beam or by bombardment with particles such as electrons. The universality of this phenomenon, the speed with which the measurements can be obtained and the potential to examine most materials without preparation all contribute to the success of this analytical method, which does not destroy the sample. However, the calibration procedure for X-ray fluorescence is a delicate operation. 

The rotationally resolved spectra of the doubly hydrogen-bonded complexes (HCOOH)2 and (CH3COOH)2 have been measured for the first time by a spectroscopic technique. Rotational constants and the PT evaluated from the fitting of the fs DFWM spectra are in good agreement with results from ab initio calculations. The values of the CD constants have been obtained from the analysis based on a new general nonrigid asymmetric rotor approach. 

Finally, highly reactive salts such as triphenylmethyl hexachloroantimonate provide very convenient scavenging agents for the removal of the last traces of nucleophilic impurities in polymerisation solvents. Penczek (35) has taken this further in developing a spectroscopic technique for the determination of trace quantities of residual water by reaction of the latter with known concentrations of triphenylmethyl salts, according to the following equilibria ... 

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