摘要:

AbstractRaman spectra of the liquid and three solid phases of cyclohexanol are reported. Disorder in Phase 1 is shown to arise from random mixing of axial and equatorial conformers with free molecule rotation being unimportant. Axial to equatorial transformation is also shown to be unlikely in the solid phase. The equatorial isomer is shown to dominate the structures of phases II and III with phase III showing, in addition, intermolecular hydrogen bonding. The dominant mechanism for dielectric loss in the plastic phase is hydroxyl group rotation with molecule libration playing a minor rôle

ISSN:0377-0486    

DOI:10.1002/jrs.1250050302

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe study of vibrational spectra ofcis‐3,4‐dimethylcyclopentanone shows that this molecule belongs to theC1symmetry group, with a half‐chair conform

ISSN:0377-0486    

DOI:10.1002/jrs.1250050303

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractA pulsed‐laser Raman spectroscopy system using a doubled Nd: YAG laser is described. Comparisons between spectra recorded using the repetitive mode (low peak power and high duty cycle) with those recorded using the burst mode (high peak power and low duty cycle) are presented showing the degree of discrimination against fluorescence and stray ambient light obtained with a gated detection system. Spectra of nylon, acrylic, benzene with acridine orange, doped SrF2crystal, and various forms of aluminum oxide and hydroxide are presented. The spectra suggest that the burst mode consistently gives, in all cases, at least a slightly improved Raman‐signal‐to‐noise ratio with some cases showing specular improvement. The results of a preliminary analysis of the Raman spectra of benzene liquid and vapor adsorbed on aluminum oxide/hydroxide powder using the gated burst mode are also presented. Although these spectra were found to differ from that of the liquid, some tentative line identities are

ISSN:0377-0486    

DOI:10.1002/jrs.1250050304

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe Raman intensity of the ν(CH) band of 1,5‐hexadiyne has been determined for different states of association; autoassociation of 1,5‐hexadiyne has been comparatively studied by Raman and infrared spectroscopy. The integrated Raman intensity of the ν(CH) band is independant of the state of association within the error

ISSN:0377-0486    

DOI:10.1002/jrs.1250050305

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractFrom study of the ν(CC) Raman band of 4‐octyne (a proton acceptor) is is shown that, whenever the solvent is respectively a poor or a good proton donor, the formation of the hydrogen bond increases or decreases the integrated intensity of the band comparatively to pure liquid. From study of the ν(CC) Raman band of 1‐octyne (an electron acceptor) it appears two groups of electron donor solvents: (i) solvents whose effect is compatible with solvent — cage model, (ii) solvents for which the intensity of the ν(CC) band depends of ionization potential, the result suggests a charge

ISSN:0377-0486    

DOI:10.1002/jrs.1250050306

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractResults are presented on near‐forward Raman scattering from low‐frequency polaritons in LiIO3obtained by the photographic method using an iodine filter for attenuation of the laser light before it enters a spectrograph. Our experiment shows that the value of dielectric transition strength of the 238 cm−1phonon mode measured by Otaguroet al.must be corrected. The clamped dielectric constant (ϵz= 5.9) was determined from polariton measurements at frequencies below the lowest transverse mode. This value is compared with those published els

ISSN:0377-0486    

DOI:10.1002/jrs.1250050307

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe Raman spectra of (24NO)2and (15NO)2have been studied at 20 K. The far infrared of (14NO)2at 20 K was also measured. The data were assigned on the basis of aC2νmolecular model. Normal coordinate calculations were performed for a variety of assignments. The assignment that yielded the best fit is presented. The solid state effects are discussed

ISSN:0377-0486    

DOI:10.1002/jrs.1250050308

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe Raman and infrared spectra of liquid samples of 1,3‐cycloheptadiene have been studied in the range 3500–100 cm−1. Using a Valence Force Field previously obtained from other conjugated dienes, the vibrational frequencies of 1,3‐cycloheptadiene are calculated for aC2andCsconformation of the molecule which both have been proposed as reasonable structures from other spectroscopic evidence. By comparison it is concluded that normal coordinate calculation and vibrational spectra are consistent with aCsconformation of the cycloheptadiene ring. On the basis of this the vibrational assignment of 1,3‐cycloheptadiene

ISSN:0377-0486    

DOI:10.1002/jrs.1250050309

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effect of electronic resonances on the cross sections for Raman scattering from localized and delocalized vibrational modes is considered for the cases where the resonance is with a localized electronic state and with a delocalized electronic state. It is concluded that resonance with a localized electronic state increases the Raman cross section of the localized mode significantly more than that of the delocalized mode while resonance with a delocalized electronic state has the opposite effect. Furthermore, a coupling of electronic states following a conformational change in a polymer is predicted to decrease the resonance Raman cross section of a localized vibrational mode. Consequently, observations of such effects will serve to identify local phonon modes in mixed molecular crystals and provide information about conformational change in biomolecules.

ISSN:0377-0486    

DOI:10.1002/jrs.1250050310

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe Raman spectra of the cubic compounds Cs2NaMCl6with (M = Eu+3, Tb+3, Er+3and Tm+3) has been observed in the region 25 cm−1<Δν<300 cm−1. The experimental results are in complete agreement with the factor group analysis which predicts the four vibrational Raman active bandsA1g,Egand 2T2g. Also, the absence of electronic Raman bands is disc

ISSN:0377-0486    

DOI:10.1002/jrs.1250050311

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY