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On the coherent vibrational phase in polarization sensitive resonance CARS spectroscopy of copper tetraphenylporphyrin (1997)

Voroshilov, Artemy ; Otto, Cees ; Greve, Jan

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 106 (1997), S. 2589-2598

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ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: Polarization sensitive multiplex spectroscopy of resonance coherent anti-Stokes Raman scattering (CARS) of copper(II)-tetraphenylporphyrin in solution (CH2Cl2) is reported. The measurements were performed in the Q band range of the porphyrin electronic absorption. Four polarized CARS spectra were resolved in 1300–1650 cm−1 Raman range and were simultaneously fitted with a single set of vibrational parameters (band positions, bandwidths, amplitudes, depolarization ratios, and phases). The obtained coherent vibrational phases of A1g, A2g, and B1g skeletal modes of the porphyrin macrocycle appeared to correlate strongly with the mode vibrational symmetry. The origin of such correlation is analyzed within a model of the third-order nonlinear electric susceptibility χ(3). The proposed model is based on multidimensional displaced harmonic oscillator in the Herzberg–Teller expansion of Raman polarizability. The coherent vibrational phases of modes of different symmetry classes are directly affected by the symmetry dependent vibronic couplings between the pairs of Qx, Qy and Bx, By electronic transitions of the porphyrin. The phase contrast between the modes of various symmetries is most pronounced near the Q00 resonance. © 1997 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.473363

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Polarization-sensitive resonance CSRS of deoxy-and oxyhaemoglobin (1995)

Voroshilov, Artemy ; Lucassen, Gerald W. ; Otto, Cees ; [et al.]

Chichester [u.a.] : Wiley-Blackwell

Journal of Raman Spectroscopy 26 (1995), S. 443-450

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ISSN: 0377-0486

Keywords: Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Notes: Polarization-sensitive coherent Stokes Raman scattering (CSRS) measurements of oxy- and deoxyhaemoglobin in aqueous solutions are reported. The excitation wavelengths used were chosen in the region of the Q absorption bands to achieve twofold electronic resonance. The dispersion profiles of all independent susceptibility χ(3) components and purely anisotropic and anti-symmetric scattering contributions were resolved within the frequency non-degenerate CSRS scheme. Eight bands of oxyhaemoglobin and five bands of deoxyhaemoglobin were observed in the range 1500-1680 cm-1. Simultaneously fitting sets of polarization spectra provided vibrational parameters (positions, bandwidths, amplitudes, phases and CSRS depolarization ratios) for each compound. Major bands were assigned to the non-totally symmetric v10, v11 and v19 modes of the porphyrin macrocycle. The phases calculated exhibited a correlation with the symmetry of the vibrations. On the basis of the spectral fits, the three additional peaks arising in the oxyhaemoglobin spectra could be ascribed to the bands of intermediate deoxyhaemoglobin. The occurrence is due to the partial photolysis of oxyhaemoglobin. Vibrational parameters of these bands were found to be essentially similar to the parameters of the bands observed in the spectra of the stable deoxyhaemoglobin. Despite the asymmetric character predicted, the major bands were all contributed to by a considerable isotropic component. A decrease in the depolarization ratio P1212R of the anomalously polarized v19 mode from 7.7 in oxyhaemoglobin to 4.3 in deoxyhaemoglobin was observed. Such a decrease in anti-symmetric character of the vibration on release of the ligand supports the occurrence of deformation of the haem ring system.

Additional Material: 4 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jrs.1250260608

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