摘要:

AbstractRaman spectroscopy was used to study the complexation in saturated ZnBr2(CdBr2)CH3CNH2O solutions at 25°C within the CN stretching region. Using the Fourier deconvolution procedure for spectral contours, the formation of the complex (CH3CN)Zn2+in saturated and unsaturated (0.2 mole fraction CH3CN) solutions of the system ZnBr2CH3CNH2O was studied. The Fermi resonance interaction between 2253 and 2290 cm−1determines opposite directions of the combination band shift for the two systems. The differences in complexation of Zn2+and Cd2+in the mixed solvent are discussed on the basis of the preferred cation solvation by the solvent

ISSN:0377-0486    

DOI:10.1002/jrs.1250250602

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractPolycrystalline TlHSO4was investigated by calorimetry (253–423 K) and by infrared (10–300 K) and Raman (10–420 K) spectroscopy. Two phase transitions are detected at 320 and 388 K. A complete assignment of the spectra of the room‐temperature phase (III) is given and the spectroscopic results are consistent with infinite chains of hydrogen bonds. This structure appears disordered above 320 K (phase II). The high‐temperature phase (I) presents the characteristic features of a plastic phase according to the spectroscopic manifestations of an increasing orientational disorder of sulphate ions. Above 360 K, a metastable phase (I′) showing a complex hydrogen‐bonded framework

ISSN:0377-0486    

DOI:10.1002/jrs.1250250603

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractIR and Raman spectra (4000–50 cm−1) of caesium hydrogensulphide and also deuterated specimens were recorded in the temperature range 6–520 K. The spectra confirm the presence of SH−…︁SH−hydrogen bonds in CsSH in contrast to other MSH compounds (M = alkali metal). The temperature evolutions of the wavenumbers and half‐widths of the SH stretching and librational modes clearly display the partly second‐order phase transitions. These are driven by thermally activated disordering of the SH−ions from the antiferroelectrically ordered low‐temperature polymorph (LTM) via a one‐dimensionally disordered middle‐temperature polymorph (MTM) to the three‐dimensionally disordered room‐temperature form (RTM) of the CsCl type. The transition temperatures between these polymorphs differ depending on the degree of deuteration, viz. 105 and 115 K and 190 and 210 K for CsSH and CsSD, respectively, owing to the greater strengths of SD−…︁SD−bonds compared with SH−…︁SH−hydrogen bonds. In the RTM, the fraction of SH−ions which form hydrogen bonds decreases with increase in temperature. The strength (νSH= 2480–2550 cm−1,rH…︁S= 275–300 pm) and geometry (H…

ISSN:0377-0486    

DOI:10.1002/jrs.1250250604

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractRotational and vibrational relaxation of pure liquid dimethyldichlorosilane (DMDCS) at temperatures of 279, 293, 308 and 323 K and in carbon tetrachloride, dioxane, chloroform and cyclohexane solutions at 293 K were studied by Raman band shape analysis. The activation energy for molecular reorientation of DMDCS molecules was determined. The experimental vibrational correlation functions were compared with the Kubo‐Rothschild and Oxtoby relationship

ISSN:0377-0486    

DOI:10.1002/jrs.1250250605

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractNon‐linear vibronic spectra of molecules in solution were considered. Probe profiles (PP) of CARS with three laser frequencies, treated as Raman four‐wave mixing (Raman FWM), were calculated and compared with excitation profiles (EP) of CARS and of spontaneous Raman scattering. It is demonstrated that the PP of Raman FWM is a characteristic that can be used instead of the EP of spontaneous Raman scattering. The dependence of the lineshape for Raman FWM was modelled. The advantages of Raman FWM are mentioned. In contrast to CARS with two lasers, it is easy to penetrate the high‐wavenumber side of the vibronic spectra and to avoid a significant absorption at the exciting wavenu

ISSN:0377-0486    

DOI:10.1002/jrs.1250250606

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe complete vibrational spectra of Eosin Y and Erythrosin B were recorded using Fourier transform Raman and Fourier transform infrared spectroscopy. The surface‐enhanced Raman scattering (SERS) spectra of these two dyes were also studied using an intensified charge‐coupled detector (ICCD) Raman spectrophotometer operated with 5 mW laser power. The intensities of the intense alternating CC bond wavenumbers of the aromatic ring at 1333 cm−1in Eosin Y and 1317 cm−1in Erythrosin B were measured as a function of the analyte concentration of these dyes. Calibration graphs of concentration of the dyes in ethanol solution against photon counts are presented. The limits of detection of these two bands in the SERS spectra were d

ISSN:0377-0486    

DOI:10.1002/jrs.1250250607

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA simple, convenient and precise technique for deconvolving the Lorentzian (true) Raman linewidth, ΓL, from the observed Raman linewidth, (Δ1/2)R[the FWHM (full width at half‐maximum) of the Raman line in question], through polynomial fitting, was developed. The precision of this technique is a consequence of the fact that the values of ΓL/(Δ1/2)R(=Y), obtained by exact numerical evaluation of the Voigt profiles for the Raman bands, were flitted to third‐ and fourth‐degree polynomials inS/(Δ1/2)R(=X),Sbeing the spectral slit width measured as the linewidth (FWHM) of a narrow spectral line recorded at the same slit settings as the Raman line. The procedure of obtaining ΓL, from the knowledge ofS,(Δν1/2)RandX, which yields better results, is discussed. Another technique of deconvolution is described and discussed, involving the measurement of Raman linewidths of a particular Raman line for about five or six different slit widths. The measured linewidths (Δ1/2)R, when extrapolated toS→ 0, give the value of ΓLdirectly. A careful comparison with the other deconvolution techniques reveals that the method of polynomial fitting is relatively more precise than other semi‐analytical deconvolution techniques, and the extrapolation technique also gives reasonably good results. The applicability of both methods was tested by taking some s

ISSN:0377-0486    

DOI:10.1002/jrs.1250250608

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractRaman and infrared spectra of solid CH2CIF (Freon 31) were recorded in both the lattice and internal mode regions for samples at temperatures between 12 and 125 K. No evidence of any solid‐state phase transition was found, but some thin‐film samples deposited at low temperatures appear to exist in a metastable phase. Spectra of the stable phase are compatible with a non‐centrosymmetric unit cell containing four molecules. Lattice peaks are assigned on the basis of geometrical and intensity argu

ISSN:0377-0486    

DOI:10.1002/jrs.1250250609

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractLangmuir monolayers of metal‐free tetra(1,1,4,4‐tetramethyl‐6,7‐tetralino) porphyrazine (HDMTLPH2) and its copper complex (HDMTLPCu) were formed on a water subphase. The surface pressure‐area isotherms were measured and the floating monolayers were transferred to various substrates. The spectra of Langmuir‐Blodgett (LB) films deposited on metal surfaces were studied. Surface‐enhanced Raman spectra of a single LB monolayer of HDMTLPH2and HDMTLPCu deposited on rough surfaces (silver‐coated tin spheres and island films of silver and gold) are reported. Reflection absorption Fourier transform IR spectra of LB films on smooth silver are also presented. The spectroscopic characterization includes the UV‐visible spectra of multilayer films on glass slides, solutions and the bulk materials. Characteristic vibrational wavenumbers are listed and used to discuss molecular orientation in

ISSN:0377-0486    

DOI:10.1002/jrs.1250250610

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

ISSN:0377-0486    

DOI:10.1002/jrs.1250250601

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY