Temperature dependence absorption

As mentioned in the previous section, the temperature-dependent absorption spectra of RCs are very important for the understanding of the molecular properties such as the electronic configurations, vibrational contributions, and transition moment relations of the Bchls in RCs. However, only in the R26. Phe-a mutant case have absorption spectra at various temperatures so far been available. Although the absorption spectra of the WT and R26 mutant RCs are available at a few temperatures like IK, 4K, 77K, and 298K, the analyzed results are not so consistent (see Table III). It may be because the preparation... 

Hynes, A. J., E. A. Kenyon, A. J. Pounds, and P. H. Winer, Temperature Dependent Absorption Cross-Sections for Acetone and n-Butanone—Implications for Atmospheric Lifetimes, Spec-trochim. Acta, 48A, 1235-1242 (1992). 

As described in the previous section, we incorporated Et as an artificial DNA base at specific sites in duplex DNA (Fig. 12.12) [44-46]. Temperature-dependent absorption and steady-state fluorescence measurements prove the intercalation of the Et moiety in duplex DNA [44], The intercalation properties of the Et moiety do not depend significantly on the local duplex environment. Interestingly, the optical properties of Et seem not to interfere with the presence of the different counterbases T, G, C or A [45]. This result is remarkable with respect to the steric demand of the Et heterocycle and indicates a bulged position of the counterbase. 

It should be possible to estimate r, the lifetime of the low-frequency Rh-C stretch using a2 and Am in Equation (5). The values for a2 = 1.2 THz and Am = 20 cm-1 yield a value for r of 0.75 ps. For a low-frequency mode that has a number of lower-frequency internal modes and the continuum of solvent modes to relax into, 0.75 ps is not an unreasonable value for the lifetime. A measurement of the Rh-C stretching mode lifetime would provide the necessary information to determine if the proposed dephasing mechanism is valid. In principle, the same mechanism will produce a temperature-dependent absorption line shift. However, other factors, particularly the change in the solvent density with temperature strongly influence the line position. Therefore, temperature-dependent line shifts cannot be used to test the proposed model. 

Unlike the triplet contributions to the absorption spectrum, the singlet contributions have a strongly temperature-dependent absorption coefficent k. A fit between the experimental spectrum of Figure 4 and calculated spectra as in Figure 3 yields T = 1900 ( 200) K for the -X 2g maximum and T = 2700 ( 200) K for the A 2 <- X 2g satellite. The difference can be explained by the different temperature dependenees of k in conjunction with the radial temperature profile of the discharge. 

Mostafavi M, Lin M, He H, Muroya Y, Katsumura Y. (2004) Temperature-dependent absorption spectra of the solvated electron in ethylene glycol at 100 atm studied by pulse radiolysis from 296 to 598 K. Chem Phys Lett 384 52-55. 

However, the fact that the time-evolution ofthe absorption spectrum ofthe solvated electron can be accurately described by the temperature-dependent absorption spectrum ofthe ground state solvated electron (Fig. 11) suggests that the spectral blue shift would be mostly caused by a continuous relaxation, or"cooling"of the electron trapped in a solvent cavity.To conclude, this analysis clearly indicates that it is not obvious to select a unique model to describe the solvation dynamics of electron in ethane-1,2-diol, and in other solvents. 

Smith, N.S. Benilan, Y. Bruston, P. The temperature dependent absorption cross sections of C4H2 at mid ultraviolet wavelengths. Planet. Space. Sci. 1998, 46, 1215-1220. 

W.S. Pegau, J.R.V. Zaneveld (1993). Temperature-dependent absorption of water in the red and near-infrared portions of the spectrum. Limnol. Oceanogr., 38,188-192. 

Rattigan O.V., O. Wild, R.L. Jones and R.A. Cox Temperature-dependent absorption cross-sections of CF3COCI, CF3COF, CH3COF, CCI3CHO and CF3COOH, J. Photochem. Photobiol. A Chem. 73 (1993) 1-9. 

Harwood, M.H., R.L. Jones, R.A. Cox, E. Lutman, and O.V. Rattigan, Temperature-dependent absorption cross sections of N2O5. J Photochem Photobiol A Chem 73, 167, 1993. 

Nicovich, J.M., and P.H. Wine, Temperature-dependent absorption cross section of the hydrogen peroxide vapor, J Geophys Res 93, 2417, 1988. 

Burrows, J. P., Richter, A., Dehn, A., Deters, B., Himmelmann, S., Voigt, S., and Orphal, J. (1999) Atmospheric remote sensing reference data from GOME—2. Temperature-dependent absorption cross sections of 03 in the 231-794 nm range, J. Quant. Spectros. Radiative Transf. 61, 509-517. 

Miura M, Cole CA, Monji N, Hoffman AS. Temperature-dependent absorption/desorption behavior of lower critical solution temperature (LCST) polymers on various substrates. J Biomater Sci Polym Ed 1994 5 555-568. 

We have emphasized the importance of the low frequency (-100 cm-i) special pair intermolecular mode of coupling strength, 0 = 100 cm-i (Huang-Rhys factor S = 1). The temperature dependent absorption spectra of Shuvalov et al. reported later show an evidence of the special pair mode of 140 cm- (S = 1.2) [13]. A recent holebuming experiment of Small and coworkers reveals several distinctive structures in the hole spectra of the special pair. The Y-hole can be attributed as a vibronic progression hole of -120 cm-i of the X-hole situated near the spectral 0-0 line [14]. 

Two concentrated Eu systems have been found to exhibit Kondo-like anomalies EuCu2Si2 and (Eu, La)Rh2. Mossbauer experiments on both systems have been performed by Bauminger et al. (1973). For the EuCu2Si2 system, which has only one site for the Eu ion, they found one temperature dependent absorption line situated between the two regions corresponding to either Eu or Eu. Previously no Eu compound had exhibited an isomer shift in this... 

The optical data provide a fascinating qualitative view of the interatomic interactions occurring in dense cesium vapor. The discussion above also demonstrates, unfortunately, how difficult it is to obtain a quantitative interpretation of the temperature-dependent absorption in cesium vapor at very high temperatures. It is particularly difficult for the experimentalist to extract the density-dependent ionization level because of the superposition of various physical effects. There is a clear need for a more comprehensive theory that incorporates all of the relevant phenomena. 

Determination of lipid phase transition within the cytoplasmic membrane in vivo by detecting the temperature-dependent absorption change at 390 nm has been described in (5). 

As we proposed elsewhere (2), low-temperature induced shifts in the light absorption spectrum of the intact Anacystis cells can be used to detect the phase-transition of the cytoplasmic membrane in vivo. The temperature-dependent absorption change (A q in intact, CP-treated cells is shown on Fig.2. 

Fig.2. Temperature-dependent absorption changes (A q in intact Anacystis cells, grown at 32°C, and CP-treated for 0 h ( ), 4 h ( ), 8 h (x), 12 h (A), 24 h (A), respectively. Cells were treated at chilling temperature for 20 min. Spectra were recorded at 25°C.

Hynes, A.J., Kenyon, E.A., Pounds, A.J., Wine, P.H. Temperature dependent absorption cross-sections for acetone and n-butanone - implications for atmospheric lifetimes. Spectrochim. Acta 48A, 1235-1242 (1992)... 

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