摘要:

AbstractThe vibrational spectra ofp‐halogenotoluenes ando‐fluorotoluene in the region of the CH3asymmetric stretchings are reported. The observed bands at 2997, 2987, 2975 and 2945 cm−1at 77 K inp‐fluorotoluene are asslgned to theB2,A1,A2andB1modes, respectively, on the basis of theC20symmetry. Two Raman bands at 2971 and 2945 cm−1at 77 K inp‐chlorotoluene are assigned to theB2andB1modes, respectively, where the former in the liquid state is a polarized band and is assigned also to theA1mode. This is also true forp

ISSN:0377-0486    

DOI:10.1002/jrs.1250150502

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe Raman and infrared spectra of the 7‐cis, 9‐cis, 11‐cis, 9‐cis, 13‐cisand 11‐cis, 13‐cisisomers of retinal have been recorded for the first time. The spectra of the all‐trans, 9‐cis, 11‐cisand 13‐cisisomers were also recorded for comparison. The isomers were isolated from a photoisomerization mixture of the all‐transisomer and their configurations were identified by means of1H NMR or Raman spectroscopy. The Raman spectra of the isomers in CCl4solution were recorded using a flow method, the 457.9 nm line of an Ar+laser and a Raman spectrometer equipped with a multichannel detector; their infrared spectra were recorded by using an FT‐IR spectrophotometer. Comparison of the Raman spectra of the mono‐cisisomers revealed key bands which, discriminate between unmethylated‐cis(7‐cisand 11‐cis) and methylated‐cis(9‐cisand 13‐cis) configurations. The key bands were related to local vibrations around the particularcisdouble bond. Unmethylated‐cisconfigurations show (1) a unique band around 1280‐1270 cm−1due to a coupled mode ofA1type (with reference to the local symmetryC2νof thecis‐CCHCHC group) consisting of the two CH in‐plane bendings and the CC stretching, (2) a stronger band at 969 cm−1ascribable to anA2‐type coupled mode consisting of the two CH out‐of‐plane waggings and the CC torsion and (3) a unique band at 563 cm−1, tentatively related to anA‐type coupled mode consisting of the CCC and CCC deformations. Methylated‐cisconfigurations show a stronger Raman band around 880 cm−1due to CMe stretchings. Raman bands

ISSN:0377-0486    

DOI:10.1002/jrs.1250150503

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe Raman spectrum of trigonal (NH4)2TiF6between room temperature and 10 K has been measured in the lattice region of the spectrum. All the four modes predicted by group theory have been observed and tentative assignments are proposed. No phase transition has been observed down to the lowest temperatures.

ISSN:0377-0486    

DOI:10.1002/jrs.1250150504

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractInfrared and Raman spectra have been recorded at various temperatures for the solld gold (I) and gold (III) coordination compounds (CH3)2SAuX (X = Cl, Br), (CH3)2SAuCl3and their perdeuteriated derlvatives. Vibrational assignments are proposed for the observed bands on the basis of modified Urey‐Bradley force field calculations. The primary force constants,K(Au‐X) andK(Au‐S), are essentially independent of the oxidation state of the gold atom. The data also show that (CH3)2S and (CH3)3P have similartrans‐directing influences in the ground state. The signs of the interaction constants in the square‐planar species, together with the slightly largertrans‐to‐sulfur Au‐Cl stretching force constant in comparison with the correspondingcisvalue, suggest that thetrans‐to‐sulfur Au‐Cl bond is stabilized relative to thecisAu‐Cl bonds by the presenc

ISSN:0377-0486    

DOI:10.1002/jrs.1250150505

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractRaman spectra have been obtained for solid iron phthalocyanine and a 10−6M solution of its tetrasulfonated derivative with Kr+laser excitation using the 6471 Å line. A normal coordinate analysis was carried out to determine assignments for the observed frequencies in terms of the various Raman active planar modes of vibration of the complex. Good agreement was obtained between calculated and observed frequencies using an adjusted valence force field (AVFF) and incorporating empirical correlations for related types of force constants. The assignments of the normal modes of vibration appear to be generally consistent with other avilable experimental and theoretical information for phthalocyanine complexes and the related metalloporphins; however, the extensive mixing of the internal coordinates within the calculated normal modes shows clearly that the assignment of specific vibrational frequencies to individual internal coordinates is not justified. Rather, the vibrational kinematics appear to involve concerted motions of the various interior and exterior ring syste

ISSN:0377-0486    

DOI:10.1002/jrs.1250150506

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe vibrational spectrum of NX4CN (X=H or D) at 77 K is reported. The splittings of the internal modes of the NX 4+ion are slight and the internal modes and the librations correspond well in frequency with those in related compounds. The observed bands are assigned on the basis of normal coordinate analysis to the crystal structure ofD 4h10andC 2ν4symmetries, where there are slight differences in the calculated frequencies by use of the same force constants. In 2NX3·XCN ν4of the NX 4+ion splits, resulting in an associated species of [X3NX…︁NX3]+. Associated species and the site of the CN−ion are discussed with CN stretchings observed in

ISSN:0377-0486    

DOI:10.1002/jrs.1250150507

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractResonance Raman spectra of tetradesmethyl‐β‐carotene were recorded using nine laser lines in the visible region. In a KBr disk at 77 K, two strong fundamental bands (1523 and 1133 cm−1) and their overtone and combination bands were observed to the fifth overtone region. Excitation profiles of nine Raman bands, including overtone and combination bands, were measured in isopentane solutions at 185 K. These were simulated by a simple two‐dimensional model based on Albrecht'sA‐term, and a reliable set of parameters corresponding to the structure differences between the excited and ground electronic states was determined. The agreement between the observed and calculated excitation profiles was excellent, showing the adequacy of the mod

ISSN:0377-0486    

DOI:10.1002/jrs.1250150508

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe Raman and infrared spectra of MgSO3·3H2O and of deuteriated and isotopically dilute samples of this hydrate were recorded from 100 to 4000 cm−1at 90–300 K and analysed with regard to the bonding structure of the water of crystallization, the space group of this compound, i.e.P212121,PnmaorPn21a, and assignment and coupling (with the H2O and D2O librations) of the internal modes of the sulphite ions. The orientational behaviour of single crystal Raman studies on isotopically dilute samples are firstly used for assigning the uncoupled OH (OD) stretching modes to the H positions in the lattice. From the three types of water of crystallization (in the case of space groupP212121orPn21a), the orientationally disordered H2O1and H2O11are involved in very strong hydrogen bonds, uncoupled OH (OD) modes 3027 (2282) and 2930 (2240) cm−1, caused by the strong hydrogen bond acceptor strength of the sulphite ions. Both water molecules are extremely distorted with OH (OD) mode splittings up to 393 (218) cm−1, the largest known so far. H2O111forms weak bifurcated hydrogen bonds. Both the stretching and bending vibrations of the sulphite ions coincide with rotational modes of the water m

ISSN:0377-0486    

DOI:10.1002/jrs.1250150509

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractA single crystal of vivianite, Fe3(PO4)2·8H2O, has been investigated at room temperature using Raman spectroscopy. Using the site symmetry method, we have identified the internal modes of the PO4group. For the stretching modes we have observed: ν1(Ag)=950.5 cm−1. ν3(Ag)=990.0 cm−1, ν3(Ag)=1052.9 cm−1and ν3(Bg)=1018 cm−1. The modes involving the motion of the iron atoms and their neighbourhood have also bee

ISSN:0377-0486    

DOI:10.1002/jrs.1250150510

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractBrillouin spectra of lithium potassium sulfate have been obtained in its hexagonal phase from room temperature to the orthorhombic phase transition temperature at 435°C. The ν11longitudinal sound velocity corresponding to theC11elastic coefficient undergoes a smooth decrease with increasing temperature; the maximum decrease is 6.0% atT0=435°C and the temperature dependence of ν11satisfies an expression of form\documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{V_{11} (T)}}{{V_{11} (293\,{\rm K})}} = A - BT - \frac{C}{{T_c - T}} $$\end{document}withB=(1.13±0.04) × 10−4K−1,C= (0.9±0.1) K andTc= (467±6)

ISSN:0377-0486    

DOI:10.1002/jrs.1250150511

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY