摘要:

AbstractNanosecond time domain transient resonant CARS (RCARS) techniques have been used to investigate photophysical transformations of Ni‐octaethylporphin (Ni‐OEP) in tetrahydrofuran (THF) solution. For the first time the RCARS spectra have been obtained from the short‐lived (280 ps) low‐lying excited electronic state3B1g, populated under the effect of intense resonant laser pulses. The amplitude‐polarization sensitive techniques of nondegenerate RCARS have been used to perform symmetry species assignments for the Raman‐active vibrational modes in the1A1gand3B1gelectronic states. Only non‐totally symmetric in‐plane vibrations of the porphyrin skeleton with theb1g,b2ganda2gsymmetry species in theD4hpoint symmetry group show up in the coherent scattering spectra under excitation within the visibleQabsorption bands. The character of electronic resonance enhancement for the RCARS process has been studied when the excitation laser frequencies match one‐photon resonances with the frequencies of vibronic transitions between the3B1gand3Q″ excited states, and excitation and probing nondegenerate RCARS profiles have been measured for the Raman modes at 1562 and 1627 cm−1. It has been found that the Raman modes intensity in the RCARS spectra from the3B1gstate is borrowed from the Herzberg–Teller scattering when resonances with the3B1g↔3Q″ transition take place. The data of the saturation degenerate RCARS experiments combined with the numerical analysis of the stationary rate equations for populations of the low‐lying electronic states made it possible to reveal the influence of the resonant radiation inte

ISSN:0377-0486    

DOI:10.1002/jrs.1250200302

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractIR, Raman and UV spectra of CF3C(O)I have been obtained and assigned to the expected vibrational normal modes of the molecule and electronic transitions in the CO group. Internal force constants were calculated from vibrational data. The results agree with data reported for other CF3C(O)X compound

ISSN:0377-0486    

DOI:10.1002/jrs.1250200303

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe infrared and resonance Raman spectra of the solid complex hydroxophthalocyaninatomanganese(III) were obtained. The excitation profiles of some vibrational modes show resonance within the electronic bands in the visible region, and on this basis several vibrational and electronic absorption bands are assigned.

ISSN:0377-0486    

DOI:10.1002/jrs.1250200304

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe Raman spectra of polycrystalline Zn (N2H4)2X2(X  Cl or Br) and Mn(N2H4)2Cl2were run over the range 90–3590 cm−1. The bands observed in the higher frequency region (400–3590 cm−1) were assigned to perturbed hydrazine vibrations and generally agree well with previously reported infrared studies. A normal coordinate analysis was performed on the core of the complexes, metal · N4X2, and used to assign the observed metalnitrogen and metal–halide bands in the lower frequency range (

ISSN:0377-0486    

DOI:10.1002/jrs.1250200305

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractPolarized Raman spectra of single crystals of lithium ammonium sulphate (LiNH4SO4) have been obtained. Detailed assignments of symmetry were made using selective scattering geometries. Separation of TO and LO components were either observed experimentally or calculated using oblique phonon frequency measurements.

ISSN:0377-0486    

DOI:10.1002/jrs.1250200306

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractRaman spectra of aqueous solutions ofL(+)‐glutamic acid were studied in the pH range 0.5–12.5. Various ionic species were identified from the spectra and the pH ranges in which they predominate were established. Solid‐state Raman spectra ofL(+)‐glutamic acid and the hydrochloride and monosodium salt were recorded and the spectra assigned and correlated with the structures of the three molecules. Near‐infrared Fourier transform Raman spectra of the three solid compounds were recorded and are compared with the spectra obtained using dispersive in

ISSN:0377-0486    

DOI:10.1002/jrs.1250200307

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractRaman spectra in the CH and SO stretching and SO bending regions are reported for solutions of lithium halides and tetrabutylammonium bromide (TBAB) in dimethyl sulphoxide (DMSO) and DMSO‐d6. The CD stretching band of DMSO‐d6shows two components in solutions of TBAB with DMSO‐d6, whereas the CH stretching band of DMSO for solutions of LiX (X = Br and I) in DMSO show some broadening and asymmetry in the low‐frequency region. The SO stretching bands show changes in band shapes and band contours in solutions of electrolytes in DMSO. Fourier deconvolution of CH and SO stretching bands were carried out to gain more information regarding number of components present under the broad structured bands. All the solutions show a significant decrease in the intensity of the SO bending bands when compared with the neighbouring CS bending band. The results are discussed in terms of anion‐ and cation–m

ISSN:0377-0486    

DOI:10.1002/jrs.1250200308

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractBrillouin scattering was performed between 80 and 300 K in order to study the hypersonic properties of Bi4Ge3O12crystals. The velocity and the attenuation of longitudinal acoustic phonons propagating along the [100] direction were measured for frequencies near 34 GHz. The Brillouin shift shows a variation with temperature which is five times lower than that observed in another bismuth germanium oxide, Bi12GeO20. The hypersound attenuation is also very low and seems to be independent of temperature.

ISSN:0377-0486    

DOI:10.1002/jrs.1250200309

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractModel calculations of the absorption and the four quantities representing third‐order non‐linear susceptibility [the real and imaginary part of the excitation profile and of the resonance background component for resonance coherent anti‐Stokes Raman scattering (CARS), R, J, b′ and b″, respectively] were carried out for polyatomic molecules. Comparison with previously acquired experimental data for bisdimethylaminoheptamethine perchlorate shows satisfactory agreement, except for b′ and b″. Some molecular parameters (the shift parameter of the active vibrations and the vibronic relaxation constant) were estimated. It is concluded that the resonance background is more sensitive to the model than the absorption and the excit

ISSN:0377-0486    

DOI:10.1002/jrs.1250200310

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractNew experimental data for depolarization dispersion (DPD) and excitation profiles (EP) with high spectral resolution (20 cm−1) are provided for Raman fundamentals of protoporphyrin IX in ferrocytochrome c between 17000 and 22 500 cm−1, covering the resonant region of theQ‐bands and the pre‐resonant region of theB‐bands. Both DPD and EPs of the lines at 1312 and 1585 cm−1(A2g), at 1363 cm−1(A1g) and at 1621 cm−1(B1g) exhibit sharp structures. These result from multi‐mode contributions of vibrations which give intensity to the vibronic sideband of theQ‐absorption. On the basis of these highly resolved new data we have shown that the Raman tensor can be formulated in terms of Loudon's strictly time‐dependent perturbation formulation to third order augmented by a fifth‐order term representing the multi‐mode effects. From the EPs, which were measured in absolute units, we obtained values of vibronic coupling parameters for the Raman fundamentals which are consistent with the optical absorption spectra and show that vibronic coupling is weak

ISSN:0377-0486    

DOI:10.1002/jrs.1250200311

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY