Infrared spectral region

One further example of this principle of bridging the aryl groups of a triarylmethane phthalide was reported in 1986.108 Thus, treatment of phthalide 27 with aluminum chloride results in the formation of the spirobenzanthracene 28 as shown in Scheme 11. These color formers also exhibit absorption in the near infrared spectral region, but no further reports of such compounds have since been published. 

Infrared spectra, of fats and oils, 10 823 Infrared spectral region, 19 564 Infrared spectroscopy, 14 224-243 23 136-143. See also Chromatography-infrared spectroscopy Far- infrared spectroscopy ir-selective surfaces Ir (infrared) spectroscopy Near- infrared spectroscopy Thermal analysis-infrared spectroscopy applications of, 14 239-240 23 140-141 in composition measurements, 20 682 in fiber optic fabrication, 11 138 industrial applications of, 14 240 instrumentation in, 14 225-228 23 137-138... 

Explain what types of quantized absorbances are expected in the ultraviolet, visible and infrared spectral regions. 

What near-infrared spectral region will be targeted for the calibration development, for example, combination region, first combination/overtone, or second combination/overtone Each region will imply a different transmission path length, and hence cell or probe design. 

E.N. Lewis, RJ. Treado, R.C. Reeder, G.M. Story, A.E. Dowrey, C. Marcott and I.W. Levin, Fourier transform step-scan imaging interferometry high-definition chemical imaging in the infrared spectral region. Anal. Ghent., 67, 3377-3381 (1995). 

A dispersive phenomenon occurring when the wavelength of scattered electromagnetic radiation in the mid-infrared spectral region is shifted relative to that of the incident beam of exciting radiation. Spectral excitation is typically measured at a nonabsorbing wavelength, and the Raman effect occurs when the polarizabihty of a bond varies with the internuclear distance, as specified by the equation ... 

The C—C bond was found to be slightly more perturbed than in the monolithium species (i.e., LiC2H4) and the Li—C interactions somewhat more rigid. The normal coordinate analysis showed that such a model is capable of satisfactorily reproducing the measured isotopic shifts on the observed 12 fundamentals. However, the very important Li—Li vibration, which could prove the proposed geometry, was not detected in the expected far-infrared spectral region ... 

Assignments for the Major Absorptions of Dorzolamide Hydrochloride in the Infrared Spectral Region... 

Fig. 31 Experimentally obtained methane absorption lines in the infrared spectral region, (a) Two isolated methane spectral lines. A smooth curve is fitted to the base line, (b) Replotted lines. All points on the smooth curve were assigned the value of zero, and all values on the spectral lines are adjusted accordingly.

Thermal emission spectroscopy can be used in middle- and far-infrared spectral regions to make stratospheric measurements, and it has been applied to a number of important molecules with balloon-borne and satellite-based detection systems. In this approach, the molecules of interest are promoted to excited states through collisions with other molecules. The return to the ground state is accompanied by the release of a photon with energy equal to the difference between the quantum states of the molecule. Therefore, the emission spectrum is characteristic of a given molecule. Calculation of the concentration can be complicated because the emission may have originated from a number of stratospheric altitudes, and this situation may necessitate the use of computer-based inversion techniques (24-27) to retrieve a concentration profile. 

Spectroelectrochemical experiments have been extended to the infrared spectral region using simple optical and electrochemical cell arrangements. Figure 9.12 shows a spectroelectrochemical cell that permits acquisition Fou-... 

Raman spectroscopy can offer vibrational information that is complementary to that obtained by IR. Furthermore, since the Raman spectrum reveals the backbone structure of a molecular entity [55], it is particularly useful in the examination of polymer film-coated electrodes. There are also some distinct advantages over in situ IR. For example, both the mid and far infrared spectral regions can be accessed with the same instrumental setup (in IR spectroscopy, these two regions typically require separate optics) [55]. Second, solvents such as water and acetonitrile are weak Raman scatterers thus the solvent medium does not optically obscure the electrode surface as it does in an in situ IR experiment. 

The application of thin-layer spectroelectrochemical techniques to the study of electrode reactions in molten salts is becoming increasingly popular. Experiments have been conducted in both the ultraviolet-visible and infrared spectral regions. Background information about thin-layer spectroelectrochemical techniques is given in Chapter 3. In addition, Norvell and Mamantov [72] have reviewed the application of spectroelectrochemical techniques to molten salts. 

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