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  • 1
    Electronic Resource
    Electronic Resource
    Dicarbocyanine dyes in methanol solution probed by depolarized Rayleigh and hyper-Rayleigh light scattering (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 8230-8236 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The hyper-Rayleigh scattering (HRS) intensity of two symmetric carbocyanine dyes (1122 DEDC and 1144 DEDC, full names given in the text) in methanol is measured as a function of dye concentration. These dye molecules at equilibrium show a negligible permanent dipole moment. The low concentration data showing that the HRS intensity is proportional to the dye concentration are used to determine the first hyperpolarizability for each of these dyes. However, above a concentration ρb=0.1×10−3 M, the HRS intensity shows an anomalous concentration dependence. Above ρb, the HRS intensity shows a saturation behavior and it even decreases with increasing concentration at high dye concentration. The depolarization ratio of the HRS intensity is also measured as a function of dye concentration. At lowest concentration, the depolarization ratio is 0.18. As the dye concentration increases, the depolarization ratio also rapidly increases but the increase quickly saturates as the concentration exceeds ρb. The concentration dependence of the HRS intensity and depolarization ratio are interpreted as due to formation of molecular aggregates. The depolarized Rayleigh scattering (DRS) intensity is also measured as a function of dye concentration. The result of DRS corroborates well with that found in HRS. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471576
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  • 2
    Electronic Resource
    Electronic Resource
    Transient absorption, time-resolved fluorescence and resonance Raman spectroscopic studies of bis(meso-tetraphenylporphyrin)zirconium and bis(meso-tetraphenylporphyrin)zirconium hexachloroantimonate (1992)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 96 (1992), S. 8374-8377 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100200a031
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  • 3
    Electronic Resource
    Electronic Resource
    Surface-enhanced Raman scattering of zinc tetrakis(4-N-methylpyridyl)porphyrin (1989)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 20 (1989), S. 739-743 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The surface-enhanced Raman spectra of zinc tetrakis(4-N-methylpyridyl)porphyrin in silver sol using various excitation wavelengths are reported. On the basis of comparison of the patterns of the relative enhancement between SERS and normal Raman bands and using previous theoretical calculations, this molecule is found to be anchored on the silver surface with ‘flat-on’ geometry. Generally, out-of-plane porphyrin and pyridyl modes are relatively strongly enhanced relative to the in-plane porphyrin skeletal modes in SERS as compared with normal Raman spectra. The mode assignment for this molecule was attempted based on the enhancement pattern of Raman modes depending on the geometry of the adsorbed molecule and the mode character. The selective enhancement of some modes would be helpful in the vibrational mode assignments of porphyrins having peripheral phenyl groups.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250201107
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  • 4
    Electronic Resource
    Electronic Resource
    Surface-induced substitution reaction on cobalt(III) and manganese(III) tetrakis (4-N-methylpyridyl)porphyrins probed by surface-enhanced Raman spectroscopy (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 21 (1990), S. 667-674 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Surface-enhanced Raman spectra of Co(III)TMPyP(4)Cl and Mn(III)TMPyP(4)Cl [where TMPyP(4) = tetrakis (4-N-methylpyridyl)porphyrin] demonstrate the formation of Ag(II)TMPyP(4) on the silver surface. The reaction is not photon assisted but is dependent on the sol activity and time. The effect of NaCl on the sol activity and the surface-induced reaction was investigated. It was observed that the metal substitution reaction of Mn(III)TMPyP(4)Cl was more efficient than that of Co(III)TMPyP(4)Cl.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250211006
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  • 5
    Electronic Resource
    Electronic Resource
    Surfactant-aided surface-enhanced Raman scattering of Zn(II), Co(II), Ni(II), Cu(II) and free-base tetrakis(4-sulphonatophenyl)porphyrins (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 23 (1992), S. 667-672 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Although surface-enhanced Raman scattering (SERS) has been recognized as a powerful tool for investigating the vibrational structure of molecules, the requirement that the molecules under study should have appropriate functional groups to interact with the metal surface has been a major problem in applying the SERS effect to many chemical or biological systems. It is shown that the introduction of a surfactant such as cetyltrimethylammonium bromide in a silver sol results in a strong Raman signal enhancement of negatively charged water-soluble metallotetrakis(4-sulphonatophenyl)porphyrins. Without introducing CTAB into a silver sol, these porphyrin molecules did not show any colour change and consequently no SERS effect was observed. Such a surfactant-aided SERS effect will provide the possibility of applying SERS to new molecular systems.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250231203
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  • 6
    Electronic Resource
    Electronic Resource
    High-frequency vibrational mode characterization of Zn(II), Ni(II) and Co(II) tetraphenylchlorins (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 21 (1990), S. 645-654 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The detailed resonance Raman spectra of metallotetraphenylchlorins with B, Qx and Qy excitations and excitation profiles of Raman modes on the Qy absorption band have been reported. In metallotetraphenylchlorins, the character of the vibrational eigenvector and the localization of the modes in the pyrrole rings raised by the symmetry are different from those of metallooctaethychlorins. A recent normal mode calculation on Cu(II) tetraphenlchlorin based on the semi-empirical quantam chemistry force field (QCFF/PI) method was utilized to elucidate the vibrational mode assignment of Zn(II), Ni(II) and Co(II) tetraphenylchlorins. For Raman excitation profiles on Qy(O, O) and Qy(O, 1) absorption bands, it is observed that some polarized Raman bands have contributions not only from A-term scattering but from Herzberg-Teller scattering. This can be explained by the symmetry lowering and the localized normal mode character of metallotetraphenylchlorins. For depolarized and anomalously polarized Raman bands, the vibronic coupling (interstate mixing) is strongly introduced.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250211004
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