IR and Raman spectroscopic studies

IR and Raman spectroscopic studies on films and powders of PDHS indicate that the hexyl side chains are crystallizing into a hydrocarbon type matrix (40). This is indicated by the presence of a number of sharp characteristic alkane bands which become dramatically broadened above the transition temperature. Similar changes are observed for n-hexane below and above the melting point. CPMAS 29Si NMR studies on PDHS also show that the rotational freedom of the side chains increases markedly above the transition temperature (41,42). All of the spectral evidence... 

As mentioned previously (Section III) IR and Raman spectroscopic studies have been carried out to elucidate the structure of the main tautomers of uracil and thymine. Although the vibrational spectra of the pyrimidine bases (e.g., refs 41, 50, 51, 55, 326, 354, 370) are difficult to interpret, a better understanding of the vibrational motions of these molecules has been possible over the past years.193,370-372 There have also been some quantum-mechanical attempts to interpret the vibrational spectra. 

IR and Raman spectroscopic studies of the ligand tetraallyldiphosphine disulfide and its zinc complex ZnLCl2 have been reported.921... 

As 1 is a nonpolar symmetric top with symmetry, it should have no pure rotational spectrum, but it acquires a small dipole moment by partial isotopic substitution or through centrifugal distortion. In recent analyses of gas-phase data, rotational constants from earlier IR and Raman spectroscopic studies, and those for cyclopropane-1,1- /2 and for an excited state of the v, C—C stretching vibration were utilized Anharmonicity constants for the C—C and C—H bonds were determined in both works. It is the parameters, then from the equilibrium structure, that can be derived and compared from both the ED and the MW data by appropriate vibrational corrections. Variations due to different representations of molecular geometry are of the same magnitude as stated uncertainties. The parameters from experiment agree satisfactorily with the results of high-level theoretical calculations (Table 1). 

A detailed IR and Raman spectroscopic study of FC(0)I gave the assignments shown in Table 7 (confirmed by DFT calculations).342 Ab initio calculations gave vibrational wavenumbers for the C12C0.H20 complex.343... 

In the solid state, unsubstituted 4-mercaptopyridine is composed of infinite chains of the thiopyridone molecules associated by NH S hydrogen bonds (92JPOC191). In contrast, 2-mercaptopyridine is associated into thione dimers, and the tautomeric equilibrium is not affected by pressure or by temperature in the 54-294 K range according to IR and Raman spectroscopic studies (94JST(324)83). 

The volatility of U(OMe)6 has recently attracted attention for laser-induced uranium isotope separation with a CO2 laser. At 330°C, U(OMe)e has a vapor pressure of IVmTorr and A/f biimation = 96 13 kJmol and AS° b,i ation = 318 17 JK mol . From IR and Raman spectroscopic studies of the O and 0 labell methoxide, a good vibrational analysis has been performed, allowing the assignments of the U— O stretching frequencies 505.0cm" ... 

Syndiotactic polystyrene rrrr>96%-, 7 = 260-270°C IR and Raman spectroscopic studies of local chain conformation in glass and gels. [156,157]... 

F Rull, J Medina, A Rivas, J Alvarez. An IR and Raman spectroscopic study of verdigris in mediaeval frescoes. In F Rull, ed. Proceedings of GEORAM AN 99, 4th International Conference Applied to the Earth Sciences. University of Valladolid, 1999. 

Jung and Bell using Zr02, have proposed the reaction sequence summarized in Scheme 6.6 [57] based on NMR, IR, and Raman spectroscopic studies. 

The introduction of microspectrosopy by coupling IR and Raman spectroscopic studies with confocal microscopes directed the research focus away from the chemical analysis of macroscopic assemblies (biofilms, whole algae communities) or extracts [138,139] to the point of studies on single individuals [140, 141] and even to the (sub)cellular level of individual cells [142, 143]. The introduction of mapping and imaging techniques enlarged the scientific view to distributional analysis in addition to the classical qualitative and quantitative determination. 

FIGURE 7.4 A pocket structure formed by the lithium association with the backbone nitrogen atom and the neighboring ether oxygen atoms. (Reprinted with permission from Luther, T.A., Stewart, F.F., Budzien, J.L., LaViolette, R.A., Bauer, W.F., Harrup, M.K., Allen, C.W., and Elayan, A., On the mechanism of ion transport through polyphosphazene solid polymer electrolytes NMR, IR, and Raman spectroscopic studies and computational analysis of N-labeled polyphosphazenes, J. Phys. Chem. B, 107, 3168. Copyright 2003 American Chemical Society.)... 

Ardelean, I., N. Muresan, and P Pascuta. 2006. FT-IR and Raman spectroscopic study of Cr203-Te02-B203-Srp2 glasses. Modem Phys. Lett. B 20 1107-1114. 

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