Near-infrared absorption

Wang C, Mohney B K, Williams R, Hupp J T and Walker G C 1998 Solvent control of vibronic coupling upon intervalence charge transfer excitation of (NC)gFeCNRu(NH3)g- as revealed by resonance Raman and near-infrared absorption spectroscopies J. Am. Chem. Soc. 120 5848-9... 

Let us close this paragraph with MMCT transitions between two ions of the same element, one with the other with d configuration. Jorgensen [56] showed long ago that the simultaneous presence in 12 M hydrochloric acid of pale yellow Ti(IV) and blue Ti(III) yields a dark brownish-purple 1 1 complex with a stronger absorption band than the single constituents have. The broad absorption band has a maximum at 482 nm. The new absorption band is ascribed to a Ti(III)-Ti(IV) MMCT transition. A near-infrared absorption band in titanium-doped AI2O3 seems to be due to the same transition [57]. 

Symmetrical and unsymmetrical quinaldine-based squaraines 14 linked to cellular recognition elements that exhibit near-infrared absorption (>740 nm) could have potential biological and photodynamic therapeutical applications [68]. 

Chan K., Ito H., Inaba H., Furuya T., Ten-kilometer long fiber-optic remote sensing of methane gas by near infrared absorption, Appl. Phys. B 1985 38 11. 

Imes, E. S. Measurements on the near infrared absorption of some diatomic gases. Astrophys. J. 50, 251-276 (1919). 

Figure 1. Near-infrared absorption changes for Rps, sphaeroides reaction centers imbedded in a PVA film at 30 ps (A) and 1,6 ns (B) with respect to the center of a 30-ps 600-nm excitation flash, at 295 K (dashed) and 5 K (solid). Reproduced with permission from Ref. 22. Copyright 1985, Elsevier Science Publishers.

G. C. Tabisz, E. J. Allin, and H. L. Welsh. Interpretation of the visible and near infrared absorption spectra of compressed oxygen as collision induced electronic transitions. Can. J. Phys., 47 2859, 1969. 

Figure 5. Near-infrared absorption spectra of H02 (top), CH302 (middle), and CH3CH202 (bottom) from the study of Hunziker and Wendt (64). (Reproduced with permission from reference 64. Copyright 1976 American Institute of...

In addition, near infrared absorption bands at 1.255 and 1.425 /tm have recently been found by Hunziker and Wendt (493), who have attributed the bands to a transition 2 A <- 2A". The band at 1.504 /emission bands of H02 have been detected recently by Becker et al. (83, 86). The H02 radical is an important reaction intermediate in combustion, in polluted atmospheres, and in the photolysis of H202. The reaction of H02 with NO is considered as a key reaction in photochemical smog formation, which is discussed in Section VIII 2. 

Triarylmethane Dyes with Near-Infrared Absorption. The long wavelength absorption bands of triarylmethane dyes can be shifted into the near-infrared region, but the dyes still remain colored because other absorption bands are shifted to or stay in the visible region. These types of triarylmediane dyes and their derivatives have been claimed as infrared absorbers for optical information recording media and security devices, and as organic photoconductors for nse in lithographic plate production. 

Here the constant b was assumed to have the same value for both the E and E states. This assumption is consistent with transition [2] being a narrow peak while transitions [3] and [4] are broader bands, as the structure of the near-infrared absorption of CuIJY demonstrates (Fig. 9). Transitions [2], [3], and [4] are assigned the observed frequencies 10900, 12700, and 14650 cm l, and transition [1] will be shown to be below 1000 cm-l. The energy difference between transitions [2] and [3] depends only on the Jahn-Teller coupling constant, which is determined to be b = 3600 cm- from the observed frequencies. The spin-orbit coupling constant X is equal to 829 cm l for the free Cu11 ion (23), but in Cu11 complexes assumes the value close to 400 cm l. In the present analysis the band centers are insensitive tj various choices of,X. With X = 400 cm and b2 = 3600 cm, the... 

In contrast to highly stable and prolific fullerene anionic species, fullerene cations are rare. The first fullerene cation was prepared in 1996 by Reed and co-workers500 by single-electron oxidation of C76 to form radical cation C76 + isolated in solid form as the CBnH6Br6 salt [Eq. (3.56)]. The cation was identified in solution by a characteristic visible-near-infrared absorption (Amax = 780 nm), FT-IR and EPR spectroscopy. C60 + was generated in an analogous way later.501 Reed et al.501 also succeded in... 

Examples of useful near-infrared absorption bands... 

Bokobza, L. (2002). Origin of near-infrared absorption bands. In Near-Infrared Spectroscopy Principles, Instruments, Applications, Siesler, H. W., Ozaki, Y., Kawata, S., and Heise, H. M., eds., Wiley-VCH, Weinheim, Germany, pp. 11-39. 

Wray S, Cope M, Delpy DT, Wyatt JS, Reynolds EOR. Characterization of the near-infrared absorption-spectra of cytochrome-Aa3 and hemoglobin for the non-invasive monitoring of cerebral oxygenation. Biochimica et Biophysica Acta 1988, 933, 184—192. 

Direct methods are based on an intrinsic property of the glucose molecule and the measurement of this property. The best example of a direct measurement is vibrational spectroscopy as implemented by near-infrared absorption spectroscopy or Raman scattering spectroscopy. A summary of the major methods is provided in Section 12.5. 

For brevity, results from selected in vitro and in vivo studies employing either near-infrared absorption spectroscopy or Raman spectroscopy, the most commonly used techniques, are documented in Tables 12.1 and 12.2. In these tables, error estimates are reported with either CV or P in parentheses, indicating cross-validated or predicted results, respectively. For an explanation of these terms, please refer to Section 12.4. 

Individual near-infrared absorption bands have absorptivities on the order of 10 1 Al /mm/mM for peak absorption bands in aqueous matrices.30 Such low absorptivities limit detection to the major components within skin tissue. As a general rule of thumb, substances must be present at concentrations above 1 mM to be quantified by near-infrared spectroscopy. Although such low absorptivities greatly restrict the number of possible analytes one can measure in clinical samples, the inability to measure chemicals present below millimolar concentrations enhances selectivity by rendering measurements insensitive to many different types of endogenous molecules. Only the major chemical components of these biological samples must be considered for selectivity purposes. 

Individual near-infrared absorption spectra are presented in Figure 13.3 for each of the mixture components. Figure 13.3 presents absorption spectra over the first-overtone and combination spectral regions, respectively. Each spectrum was collected from 100 mM solution of the selected solute dissolved in a pH 6.8 phosphate buffer solution and absorbance was calculated relative to a reference spectrum of the blank phosphate buffer. 

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