Resonance Raman scattering and vibronic coupling in aquo‐ and cyano‐cobalamin

Galluzzi, F.; Garozzo, M.; Ricci, F.

doi:10.1002/jrs.1250020405

Cited by 35 publications

(17 citation statements)

References 28 publications

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“…Several approximations are introduced to evaluate fa: (a) harmonic oscillator wave functions are assumed for the g and e states, (b) it is assumed that no change in force constant occurs in the upper state, and (c) it is assumed that the potential energy curves are displaced from each other horizontally by a parameter x such that x = (Vb.,1,7r/h)1/2Q (4) Computer programs were written to calculate and plot the excitation profiles. The sum over u was taken up until u = 6.…”

Section: Theoreticalmentioning

confidence: 99%

Correlation between the absorption spectra and resonance Raman excitation profiles of astaxanthin

Salares¹,

Mendelsohn²,

Carey³

et al. 1976

J. Phys. Chem.

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Publication costs assisted by the National Research Council of CanadaResonance Raman excitation profiles in the region 4579-5287 8, are reported for the carotenoid molecule astaxanthin at -162 and 23 "C. At these temperatures the visible absorption spectra are structured and unstructured, respectively. The experimental data, simulated using a simple model, demonstrate that there is a correlation between the development of vibrational structure in the absorption spectrum and in the excitation profile. For astaxanthin the excitation profiles a t room temperature do not resolve the vibrational structure of the broad absorption band but do show that the 0-0 transition occurs near 18 850 cm-l.

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Section: Theoreticalmentioning

confidence: 99%

Correlation between the absorption spectra and resonance Raman excitation profiles of astaxanthin

Salares¹,

Mendelsohn²,

Carey³

et al. 1976

J. Phys. Chem.

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“…The peak at 425 cm -1 , which may be assigned to Co-N bond stretching, disappears after 80 min, as shown in Figure 9(d). [44][45][46][47][48] It is implied that the Co-N bonds have been cleaved at this stage. The peak at 335 cm -1 , which is assigned to the adenine stretching vibration mode, disappears simultaneously.…”

Section: Investigation Of Reaction Kineticsmentioning

confidence: 99%

“…Therefore, RR spectroscopy was applied to monitor the process of TiO 2 -assisted photocatalytic decomposition of vitamin B 12 (Figure 9). Assignments were made on the basis of the RR spectra of vitamin B 12 , 35,[39][40][41][42][43][44][45][46][47][48] and the changes of characteristic peaks are listed in Table 2. The weak peak at 481 cm -1 in Figure 9(a), assigned to the Co-CN stretching vibration mode, does not appear in Figure 9(b).…”

Section: Investigation Of Reaction Kineticsmentioning

confidence: 99%

“…The intensities of the peak at 1500 cm -1 assigned to the C＝C stretching mode in the corrin ring and other peaks related to corrin ring stretching vibration modes gradually decrease. 43,48 It is supposed that even though the structure of the corrin ring in vitamin B 12 is stable, it can be photodegraded through weakening of the C＝C bonds. The peak at 2992 cm -1 , assigned to the ＝CH 2 symmetrical stretching vibration mode, 39 clearly decreases with a shift of 8 to 3000 cm -1 after 145 min.…”

Section: Investigation Of Reaction Kineticsmentioning

confidence: 99%

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TiO2-assisted Photocatalytic Degradation of Vitamin B12 in Aqueous Solution:Influencing Factors, Kinetics, and Reaction Investigations

et al. 2011

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The photodegradation (λ＝365 nm) of the biomolecule vitamin B 12 , catalyzed by the photocatalyst TiO 2 nanoparticles (NPs), has been investigated in aqueous suspension. The photodegradation process of vitamin B 12 has been monitored by means of electronic absorption (Abs), Fourier-transform infrared (FT-IR), and resonance Raman (RR) spectroscopies, respectively. The results show that only under UV illumination in the presence of TiO 2 is there effective degradation, and the photocatalytic degradation of vitamin B 12 is strongly influenced by the amount of TiO 2 NPs, the pH, and the initial concentration of vitamin B 12 . The photocatalytic reaction kinetics of vitamin B 12 conforms to a Langmuir-Hinshelwood isotherm model. Changes involving the three structural units of the carbon-metal bond C-Co, the organic corrin macrocycle combined with the benzimidazole nucleotide, and the inorganic CN in the vitamin B 12 molecule during the photocatalytic degradation are also discussed.

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“…During the last few years there has been a growing activity, both experimental and theoretical, in the field of resonance Raman scattering (RRS) from molecules [1][2][3][4][5][6][7][8][9][10][11][12]. It has been shown that RRS is a very useful tool for the investigation of molecular properties in excited states.…”

Section: Introductionmentioning

confidence: 99%

Depolarization dispersion of a fundamental line of a totally symmetric vibration in resonance Raman scattering

Zgierski¹

1976

J Raman Spectroscopy

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Vibronic coupling of the Herzberg-Teller type is discussed as a possible source of the depolarization dispersion of a fundamental line of a totally symmetric vibration in resonance Raman scattering (RRS). Two cases are discussed separately. The first case concerns RRS from an electronic state that borrowspart of its intensity from a non-overlapping electronicstate of different symmetry. In this case the depolarization ratio of the fundamental line for right angle scattering linearly polarized light can vary between the limits Q and $. The second case arises when part of the intensity is borrowed from an electronic state of the same symmetry but with a transition moment non-parallel to that of the resonant state. Such a situation can occur in molecules with a symmetry corresponding to one of the following point groups: C . In this situation the depolarization ratio pi can vary between the limits; and Q). In both cases the amplitude of the variations of p, depends on the damping constant. In the second case the value of the displacement parameter of a totally symmetric mode has a major influence on the range of change of p,. Both cases show prominent resonance-antiresonance coincidences between depolarization dispersions and excitation profiles, which has been previously predicted for non-totally symmetric modes, and for molecular dimers. It is pointed out that the depolarization ratio in the preresonance region is very sensitive to vibronic coupling and can serve as a probe of such coupling.

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Resonance Raman scattering and vibronic coupling in aquo‐ and cyano‐cobalamin

Cited by 35 publications

References 28 publications

Correlation between the absorption spectra and resonance Raman excitation profiles of astaxanthin

Correlation between the absorption spectra and resonance Raman excitation profiles of astaxanthin

TiO2-assisted Photocatalytic Degradation of Vitamin B12 in Aqueous Solution:Influencing Factors, Kinetics, and Reaction Investigations

Depolarization dispersion of a fundamental line of a totally symmetric vibration in resonance Raman scattering

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