摘要:

AbstractThe infrared and Raman spectra of solid 1,12‐dicarbaclosododecaborane have been studied over the temperature range 10–320 K. Three phases exist in this temperature range. Phases I and II are plastic; phase III is orde

ISSN:0377-0486    

DOI:10.1002/jrs.1250070502

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractRaman spectra have been recorded ford0,d1andd9pivalic acids and pivalic anhydride in the liquid phase and in solution in CCl4. A complete assignment of the bands is proposed and discussed specially in relation to dimerization and eventual breaking of dimers. The potential energy for hindered rotation of the CH3groups is calculated.

ISSN:0377-0486    

DOI:10.1002/jrs.1250070503

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe Raman spectra of 10 isotopic species of polycrystalline NMA were recorded at 35 K between 6 and 200 cm−1. Below 110 cm−1at least 8 transitions are observed which are mainly due to external modes. Bands located between 110 and 170 cm−1show unexpected isotopic effects and are interpreted taking into account IR and NIS spectra. A new internal torsional mode around the bond is proposed. The corresponding potential function involves two minima (Δω = ± 10°) separated by a weak barrier (∼600 cal/mole) indicating a nonplanar molecul

ISSN:0377-0486    

DOI:10.1002/jrs.1250070504

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractRaman spectra of both polycrystalline samples and single crystals of CsAlCl4and RbAlCl4(space groupPnma(D 2h16)) have been recorded in the temperature range 298–80 K.As for the other chloroaluminates, we find the four characteristic bands of the tetrahedral AlCl 4−anion at 353, 128, 485–503, 180–187 cm−1and 356, 127, 486–505 and 180–187 cm−1, respectively, for the salts CsAlCl4and RbAlCl4. The Raman spectra of single crystals of these two compounds are similar and show that these two salts are isostructural. An assignment of the observed bands is proposed. The results are compared with those for the polyatomic cation (nitrosyl and ammonium) te

ISSN:0377-0486    

DOI:10.1002/jrs.1250070505

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractNormal and resonance Raman effects in gaseous chlorine were carefully studied with a powerful argon ion laser. No resonance Raman behaviour could be detected in the spectra excited by visible laser lines with wavelengths down to 4545Å. The fine structures of the normal Raman spectra were examined. Resonance Raman spectra were obtained with the 3638 and 3511 Å UV line excitation. Progressions with seven overtones were recorded. The fine structures in each overtone region were analysed and assigned as the Q and S band heads of various isotopic molecules. The Raman cross‐section was enhanced only by a factor of 1.3 in the resonance case and the integrated intensity of each overtone was about one‐third of that of the fundamental. Those two characteristics indicate that the resonance Raman term in gaseous chlorine is small in comparison with the normal Raman term even when the energy of the excitation laser line is 7593 cm−1above the dissociatio

ISSN:0377-0486    

DOI:10.1002/jrs.1250070506

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractAcid and basic solutions of15N and D substituted guanines have been investigated by infrared and Raman spectroscopy. Monoanion and dianion formation have been followed by spectra changes; N7, N9H tautomery has also been studied by comparing with methylated derivatives. Assignment of the band frequencies have also been proposed. Analysing15N results have permitted precise comparisons between the neutral form spectra and the anionic or cationic form spectra.Abbreviations used: IUPAC‐IUB abbreviations are used throughout: m7−Gua or m7‐guanine: 7‐methyl‐gua

ISSN:0377-0486    

DOI:10.1002/jrs.1250070507

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe mean polarizability derivatives of CH4, C2H2, C2H4and C2H6are calculated through a variational procedure. Satisfactory numerical results are obtained using the CNDO approximation with polarization functions included in the basis set. The frequency dependence of the means polarizability derivative is examined, and the separate contributions from σ and π electrons are calculated for the ethylene molecul

ISSN:0377-0486    

DOI:10.1002/jrs.1250070508

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe orientational dynamics of liquid allene has been studied by means of the analysis of the isotropic and anisotropic profiles of the symmetricalA1band at 1074 cm−1and of the anisotropic profile of anEband at 3067 cm−1. These profiles have been studied in the temperature range from 300 to 150 K and for pressures ranging from 100 to 3000 atm.Using the hypothesis of a diffusional rotation, the analysis of the former band allows the determination of the principal componentD⊥of the diffusion tensor, as well as of the associated activation energy and activation volume. The comparison of the observed orientational correlation times with the free‐rotation times and the shape of the correlation functions are not in too bad agreement with this hypothesis. The second band ofEsymmetry, which corresponds to a vibration whose Coriolis constant is very small, allows the evaluation of the diffusional ConstantD∥associated to the rotation of the molecule about its axis. A strong anisotropy in the rotations of the allene molecule in the liquid state is evidenced:D∥/D⊥≃ 7. Furthermore, the rotational motion about the axis seems to digress from a diffusional motion more than the reorientation of the axis itself. Finally, the paper discusses those conditions in which the evaluation of the rotational diffusion constant from the Raman profile of a depolarize

ISSN:0377-0486    

DOI:10.1002/jrs.1250070509

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe Raman spectra of 79 nitrogen containing organic compounds have been recorded. The frequencies of amines, pyridines, cyanides, amides and nitro‐compounds are reported and correlations with the structure have been established by means of computer searching. The collected data have been incorporated into an interpretation system for C, H and O compounds, and difficulties in the interpretation of the data are reviewed. A further extension of the system is discusse

ISSN:0377-0486    

DOI:10.1002/jrs.1250070510

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe Raman spectrum of tryptophan has been observed in its neutral aqueous solution with 514.5, 488.0, 457.9, 363.8, and 257.3 nm excitation. The effects ofN‐deuteration and15N‐substitution of the indole ring on the Raman spectrum have been examined. A preliminary normal coordinate treatment of the indole ring has also been made. On the basis of these data, the vibrational mode and a possible origin of the Raman scattering intensity has been discussed for each of the 1623, 1555, 1436, 1344, 1016, 882, and 762 cm−1Raman lines of tryptophan. The resonance enhanced line at 1623 cm−1has been assigned to a vibration of the indole ring which is related to theb3gring stretching vibration of naphthalene at 1636 cm−1. Its intensity is considered to come almost solely from theB̃←X̃(La) electronic transition at 273 nm. It is therefore probable that the geometrical structure of the molecule is distorted along this vibrational coordinate on going from the ground (X̃) to theB̃electroni

ISSN:0377-0486    

DOI:10.1002/jrs.1250070511

出版商:John Wiley&Sons, Ltd.    

年代:1978

数据来源: WILEY