Infrared spectrum isotope effect

Since the C—H stretching vibration appears in the infrared spectrum around 3000 cm-1, the isotope effect at T = 300°K would be... 

Only An(III) and An(IV) ions have been inserted into macrocyclic crown-ethers, e.g., in [UCl3(18-crown-6)]2[U02Cl3(OH)H20]. Hydrogen bond interactions between etheric oxygen and coordinated water molecules were only observed in the corresponding U02+ complexes [282]. The infrared spectrum and isotope effect of uranium-crown-ether complexes were reported [435], as well as the crystal structures... 

This experiment is concerned with the rotational fine structure of the infrared vibrational spectrum of a linear molecule such as HCI. From an interpretation of the details of this spectrum, it is possible to obtain the moment of inertia of the molecule and thus the intemuclear separation. In addition the pure vibrational frequency determines a force constant that is a measure of the bond strength. By a study of DCI also, the isotope effect can be observed. 

The infrared bands around 1450-1500em in the spectrum of BFa that are assigned to the asymmetric B—F stretching mode show marked splitting because of the presence of significant amounts of both B and B in natural boron, yet the Raman band at 888 cm , assigned to the symmetric B—F stretch, shows no such isotopic effects. What can you deduce from these observations ... 

Vendrell O, Gatti F, Meyer H-D. Strong isotope effects in the infrared spectrum of the zundel cation. Angew Chem Int Ed 48 352-355... 

Instructional programs relying on home-built scanning monochromator systems and low-power lasers have usually been limited to simple demonstrations of spectra of neat liquids. Carbon tetrachloride has been a perennial favorite because the spectrum is strong and easily interpreted [7,10]. A comparison of the spectra of carbon tetrachloride, chloroform, and methylene chloride is also common, as is a comparison of the spectra of benzene and cyclohexane. Even with these systems, polarization effects can be demonstrated and selection rules taught. Details of the vibrational spectra, particularly chlorine isotope effects, may be difficult unless the instrument resolution is 5 cm or better. Because FTIR instruments are generally available, comparison of the Raman and infrared spectra of liquids is often stressed. 

Infrared spectral data are consistent with the ionization behavior of the perdeutero compound in that the major isotope effects on the spectrum account (cf. eq. 17) for the sign and, approximately, the... 

An important task for theory in the quest for experimental verification of N4 is to provide spectral characteristics that allow its detection. The early computational studies focused on the use of infrared (IR) spectroscopy for the detection process. Unfortunately, due to the high symmetry of N4(7)/) (1), the IR spectrum has only one line of weak intensity [37], Still, this single transition could be used for detection pending that isotopic labeling is employed. Lee and Martin has recently published a very accurate quartic force field of 1, which has allowed the prediction of both absolute frequencies and isotopic shifts that can directly be used for assignment of experimental spectra (see Table 1.) [16]. The force field was computed at the CCSD(T)/cc-pVQZ level with additional corrections for core-correlation effects. The IR-spectrum of N4(T>2 ) (3) consists of two lines, which both have very low intensities [37], To our knowledge, high level calculations of the vibrational frequencies have so far only been performed... 

The metal isotope technique has been used to study the effect of magnetic crossover on the low-frequency spectrum of Fe(phen)2(NCS)2. This compound exists as a high-spin complex at 298 K and as a low-spin complex a( lOO K. Figure 111-12 shows the infrared spectra of Fe(phen)2(NCS)2 obtained by Takemolo and Hutchinson. On the basis of observed isotopic shifts, along... 

Isolithobilianic-(2 3) acid, VIII, 263 Isonicotinic acid, effect on root growth, VI, 235 17-Isopregnan-3a-ol-20-one, X, 277 infrared absorption spectrum, VII, 346 as metabolite of progesterone, X, 278 structure, VII, 346 a -Isostrophantic acid, structure, VIII, 268 Isostrophantic acids, configuration, VIII, 268 Isotopes,... 

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