摘要:

AbstractThe anomalous temperature dependence of the linewidth of the νs(H2O) symmetric stretch vibration in hexa‐aquo metal (II) hexafluorosilicate (IV) salts is discussed in terms of anharmonic interactions. It is shown that the main contribution to the linewidth is an elastic scattering process between νs(H2O) and the torsional vibration of the water molecules leading to a pure vibrational dephasing. Contributions to the linewidth due to inelastic decay into other vibrational states are also discus

ISSN:0377-0486    

DOI:10.1002/jrs.1250110103

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractRaman spectra oftt‐butyl formate HCOOC(CH3)3were recorded in various solvents in the ν(CO) region and below 1000 cm−1where appear the bands sensitive to the conformation. It is shown that, compared to the pure liquid, thecis‐transequilibrium is shifted towards thetrans, the more polar form, in polar solvents and towards thecisform in non‐polar solvents. For binary solutions HCOOC(CH3)3‐Ba(ClO4)zand ternary solutions HCOOC(CH3)3‐Ba(ClO4)2‐CH3CN, the infrared and Raman spectra, recorded in the same regions, show that the complexation of the ester carbonyl group by the Ba2+cations favours thetransconformation as do the polar solvents. Through spectral analysis of the concentrated Ba(ClO4)2ester solution and of the solvation number it is shown that the Ba2+cation is octahedrally surrounded by the carbonyl groups of six molecules in its first

ISSN:0377-0486    

DOI:10.1002/jrs.1250110104

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractVitreous biomaterials with chemical composition similar to that of bone may be formed by treating mixtures of vitreous sodium polyphosphate, Graham's salt and hydroxylapatite. The Raman and infrared spectra of a range of such materials are reported and discussed in relation to their structure.

ISSN:0377-0486    

DOI:10.1002/jrs.1250110105

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractRaman spectra of a single crystal K2H2C4O4.2H2O and of polyrystalline K2H2C4O4.2H2O, K2H2C4O4.2D2O, and K2H2C4O4have been recorded at room temperature from 10 to 3500 cm−1; Raman and infrared data are compared. The existence of hydrogen bondCH…︁O is co

ISSN:0377-0486    

DOI:10.1002/jrs.1250110106

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractResonance Raman spectra (excited at 413.1 nm) and excitation profiles (Q‐band region) of cytochromeb562and cytochromecwere obtained with a sensitive vidicon multichannel Raman spectrometer.7Comparison of the spectra reveals that two Raman lines at 690 and 700 cm−1in cytochromecmay be assigned to CS stretch of the thioether bridges, which are absent in cytochromeb562. Four sets of doublet between 320 and 430 cm−1are unique in cytochromecamong various hemoproteins may indicate the existence of two subtly distinct heme structures alternating in the ground state of cytochromec.This unique spectral feature was not observed in heme octapeptide (reduced form in 0.25 MN‐acetyl‐methionine) which also contains the covalent thioether linkages. In addition, we compare the excitation profiles of a depolarized porphyrin ring mode at ∼ 750 cm−1among cytochromec, cytochromeb562and Ni etioporphyrin. The effect of a Jahn‐Teller distortion observed in the 750 cm−1profile of Ni etioporphyrin19is shown to be absent in cytochromec.The 750 cm−1profiles in theQ‐band region are interpreted in terms of Herzberg‐Teller (B) and nonadiabatic (D) contributions with o

ISSN:0377-0486    

DOI:10.1002/jrs.1250110107

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe resonance Raman spectrum of the transient thioether radical cation dimer complex |(CH3)2S|2+·, generated by electron irradiation of an aqueous solution of dimethylsulfide and recorded by optical multichannel detection, is reported. Vibrational bands at 276 cm−1and 139 cm−1were detected and are assigned to the stretching mode of the quasi‐three‐electron SS bond and a δ(CSS) deformation mode, r

ISSN:0377-0486    

DOI:10.1002/jrs.1250110108

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe Raman spectrum of the binuclear transition metal complex copper(II) acetate monohydrate is examined with various excitation wavelengths in the spectral range 17 500 to 25 000 cm−1. Nontotally symmetric vibrations are predominant in the Raman spectrum, and the depolarized Raman bands observed at 320 and 948 cm−1exhibit marked intensity de‐enhancement as the excitation wavelength approaches the dimer‐associated, Laporte‐forbidden ligand‐field transition at 26 500 cm−1. The intensity de‐enhancement observed for the nontotally symmetric vibrations of copper(II) acetate is in contrast to that observed for other centrosymmetric transition metal complexes studied thus far in which only the totally symmetric vibrations exhibit antiresonance effects. The excitation profiles are calculated for the Raman bands of copper(II) acetate using a model in which the scattering intensity arises from two termsIα|Be+Bf|2, whereBfcouples two charge‐transfer states at 35 000 and 40 000 cm−1respectively, andBecouples the ligand‐field state to the charge‐transfer state at 35 000 cm−1. The calculated profiles are in good agreement with those observed and predict that the system origin for the ligand‐field transition

ISSN:0377-0486    

DOI:10.1002/jrs.1250110109

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe Raman spectrum of gaseous trichloroacetaldehyde (chloral) has been recorded from 20 to 3200 cm−1. A series of three transitions (83, 76, 69 cm−1) has been observed for the low frequency torsional mode. The barrier to internal rotation has been calculated to have a value of 1.17 kcal mol−1(409 cm−1) in the gaseous phase. This value is compared to the corresponding quantity in similar mo

ISSN:0377-0486    

DOI:10.1002/jrs.1250110110

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractResonance Raman spectra are reported for the purple intermediate formed in the reactions of [Fe(II)(EDTA)]2−and [Fe(III)(EDTA)]−with O2−and H2O2, respectively, using several different excitation wavelengths. The spectra show only two resonance‐enhanced bands, at 472 and 824 cm−1. The band intensity excitation profiles for these two are different, demonstrating that the resonance effects observed are associated with two different electronic transitions. The 472 cm−1band is assigned to the ν(FeN) mode and the 824 cm−1band to ν(OO). The structure of the species is shown to be the peroxide ion complex [Fe(III)(EDTA)(O2)]−. The O22−→ Fe3+electronic charge‐transfer trans

ISSN:0377-0486    

DOI:10.1002/jrs.1250110111

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractResonance Raman spectra are reported for the short‐lived blue intermediate formed in the Cr(VI)‐H2O2reaction in strongly acidic aqueous solution using several different excitation wavelengths. The spectra show a number of bands which are assigned to the different ν(CrO) modes and to the ν(OO) mode within the structure CrO5·H2O. The Raman band intensity profiles indicate that the resonànce effect is associated with the 590 nm absorption band, which is assigned to the charge‐transfer transition OCr(VI). The instability of the species is interpreted on the basis of the relatively low ν(CrO) and high ν(O

ISSN:0377-0486    

DOI:10.1002/jrs.1250110112

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY