摘要:

AbstractFourier transform (FT) Raman spectra were obtained for water and aqueous solutions in a stainless‐steel, windowless, liquid captive cell of simple design. It was demonstrated that high‐quality Raman spectra in the low‐wavenumber region (down to 100 cm−1) can be obtained from highly colored samples without the presence of interfering bands from the usual sample containers made of glass or plastic. Raman bands at 520 and 232 cm−1due to the symmetric stretching modes of the Cr‐O vibration of the Cr(H2O) 63+and the Cr‐Cl vibration of the CrCl 63−complexes were observed for very dark samples that are not amenable to conventional Raman techniques. FT‐Raman studies of aqueous Cr(III) solutions can provide valuable information on the slow

ISSN:0377-0486    

DOI:10.1002/jrs.1250260502

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSurface‐enhanced Raman scattering (SERS) spectroscopy was used to explore the electrochemical reduction of CO2at a polycrystalline Ag electrode in KHCO3aqueous solution saturated with CO2at room temperature. Raman scattering from the oxidation‐reduction cycled Ag electrode suggests the formation of CO and HCOOH by CO2reduction. At an electrode potential of 0.08 V (vs.Ag/AgCl), adsorbed CO gives rise to a C‐O stretch band at 2128 cm−1. This band decreases in intensity and shifts to higher wavenumber with an increase of negative potential in the range from 0.0 to − 0.24 V. A different potential dependence is observed for the C‐H stretch mode of adsorbed HCOO−(2870 cm−1at − 0.8 V). The O‐C‐O antisymmetric and symmetric stretch modes of HCOO−observed at near 1550 and 1350 cm−1decrease in intensity with increasing negative potential, presenting a striking contrast to the C‐H stretch mode. The SERS experiment with a CO2‐saturated KHCO3D2O solution

ISSN:0377-0486    

DOI:10.1002/jrs.1250260503

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractFrom Raman spectra, the low‐wavenumber range profile (10‐200 cm−1) of planar molecules C6H6, C6F6and of their binary mixtures in the liquid state was recorded at intervals of 1°C from 10 to 65°C. The analysis was made using a reduced intensity ratioRinvolving the integrated intensity of a constructedI(v)v2spectrum and the recordedI(v)spectrum. The study ofRagainst a slow and gradual variation of temperature emphasized a break in the gradient for pure liquids. This effect is related to a change in the local environment of the molecules. This break did not appear in the study of a 1:1 mixture owing to its strong stability due to a face‐to‐face co

ISSN:0377-0486    

DOI:10.1002/jrs.1250260504

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractDi(diaminophosphoryl)imide (PNH), NH[P(O)(NH2)2]2, has very interesting fireproof properties when linked to cellulosic material. The PNH structure, hitherto unknown, was first established by x‐ray diffraction and was found to be monoclinic (P21/c,a=5.206,b=8.311,c=14.889 Å, β = 92.86°,Z=4). Based on this structure, a normal coordinate analysis was undertaken which has permitted the assignment of most of the observed IR and Raman bands in the spectral range above 1000 cm−1. More particularly, the calculated NH2stretching wavenumbers are consistent with the different hydrogen bond strengths indicated by x‐ray diffraction measurements. In the spectral range below 1000 cm−1, strong couplings between the NH and the PNH modes prevented a rigorous assignment of the obse

ISSN:0377-0486    

DOI:10.1002/jrs.1250260505

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSome 5‐(aryl)azoquinolin‐8‐ol derivatives were studied by resonance Raman, Fourier transform IR and electronic spectroscopic techniques. Analysis of vibrational and electronic spectra was used to determine the azo and hydrazone forms in both the solid and solution states. In the solid state, the compounds remain dominantly in one form and the characteristic bands due to each resonating form were identified. Various structural motifs for protonated, neutral and deprotonated states were proposed based on pH‐dependent studies. The effect of H‐bonding in stabilizing a particular type of structure is also

ISSN:0377-0486    

DOI:10.1002/jrs.1250260506

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe optical and Raman spectra of several salts of rhodizonic acid were investigated, aimed at a better understanding of the dramatic dependence of their colours on the nature of the cation. The results indicate that in addition to the maxima observed in the optical spectra, another transition in the red edge must be present in the solid state, as indicated by the large number of overtones and combination bands in the Raman spectra excited in the red. It is suggested that such a low‐energy transition observed only in the solid state is of intermolecular origin, as observed previously for other related system

ISSN:0377-0486    

DOI:10.1002/jrs.1250260507

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractRaman spectroscopy, together with factor analysis and band resolution techniques, was used to study complex formation in binary mixtures ofp‐cresol and propionitrile in the concentration range 0.025‐0.651 mole fraction ofp‐cresol. The envelope of the C  N stretching band of propionitrile in the Raman spectrum between 2300 and 2200 cm−1was studied. Factor analysis indicated that there were only two linearly independent components in the band envelope. The appearance of a pseudo‐isosbestic point in the area normalized spectra supported this conclusion. For all concentrations, the C  N stretching band envelope was resolved into three components. These were assigned in turn to the free propionitrile, a 1:1p‐cresol‐propionitrile complex and an overtone or combination mode of propionitrile which does not involve C  N stretching. The equilibrium constantKcfor the formation of the complex was determined at various mole fractions ofp‐cresol. The calculated values ofKcexhibited a strong con

ISSN:0377-0486    

DOI:10.1002/jrs.1250260508

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSERRS intensity patterns versus surface molecular coverage, both at room temperature and at low temperature (liquid N2), were studied using mixed Langmuit‐Blodgett (LB) monolayers of tetra‐tert‐butylvanadyl‐phthalocyanine and lutetium bisphthalocyanine with arachidic acid. The role played by temperature variations in the surface coverage dependence and SERRS intensity patterns is a

ISSN:0377-0486    

DOI:10.1002/jrs.1250260509

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effect of ethanol on the surface‐enhanced Raman scattering (SERS) of water molecules in a 0.5 M KCI‐water‐silver electrode system was studied by observing changes in the SERS band of water as a function of the time of ethanol addition during the oxidation‐reduction cycle. Hydrogen bond breaking, the main role of ethanol, in the SERS system of water‐ethanol seems to be a necessary condition but not a sufficient condition for observing SERS of water. Surface adatoms of Ag0‐Cl−should also be available at the time of the hydrogen bond breaking by e

ISSN:0377-0486    

DOI:10.1002/jrs.1250260510

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0377-0486    

DOI:10.1002/jrs.1250260501

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY