Resonance Raman spectra of and vibronic coupling in Ni(II) pheophytin a

Mattioli, Tony A.; Haley, L. V.; Koningstein, J. A.

doi:10.1016/0301-0104(90)87012-z

Cited by 9 publications

(7 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As expected for a vibration polarized along the yaxis, the stretching mode of the keto carbonyl is very active in Q,-preresonant spectra of both Chl a and Pheo a excited at 1064 nm," and was clearly observed in &,-resonant spectra of Ni-Pheo a. 16 Its absence from Q,-resonant, SERRS spectra of Chl may thus result from unfavorable factors specific to the surface-enhancement mechanisms. The keto and acetyl CO stretching modes of BChl a are relatively more active at Qy preresonance than at Soret r e~o n a n c e .…”

Section: Carbonyl Stretching Modesmentioning

confidence: 62%

“…'', 13 Valuable data also were provided by studies of nonfluorescent derivatives of chlorophylls resulting from substitution of the magnesium with iron,l' or nickel. 16 The breakthrough actually was achieved by more-classical Raman methods, and was made possible by recent methodological and technical progress. Two lines of progression may currently be distinguished 1.…”

Section: Technical Aspectsmentioning

confidence: 99%

See 1 more Smart Citation

Red‐band resonance raman spectroscopy of chlorophyll cofactors in photosynthetic proteins

Lutz

1995

Biospectroscopy

View full text Add to dashboard Cite

SYNOPSISOnly recently have various methodological approaches been successful in producing Raman spectra of chlorophylls resonantly with their lowest singlet electronic transitions ( Qy bands). The information content of these new approaches and their impact on current research on photosynthetic proteins are discussed. It is shown that resonance methods can contribute very valuable data on the dynamics of the primary photophysical events, while preresonance methods are yielding many new data on the structural bases of these events at atomic level.

show abstract

Section: Carbonyl Stretching Modesmentioning

confidence: 62%

Section: Technical Aspectsmentioning

confidence: 99%

Red‐band resonance raman spectroscopy of chlorophyll cofactors in photosynthetic proteins

Lutz

1995

Biospectroscopy

View full text Add to dashboard Cite

show abstract

“…No terms are included in our calculation to allow us to model non-Condon contributions to the Raman scattering. Several studies of porphyrins and pheophytins show that some modes have up to 40% contributions to their Q y REPs from non-Condon scattering sources (see for example refs and ). It would be necessary to measure the 0−1 part of the REPs, which for many of the B modes lie in the same spectral region as the H absorption band, to determine whether non-Condon scattering may be occurring.…”

Section: Discussionmentioning

confidence: 99%

Electronic and Nuclear Dynamics of the Accessory Bacteriochlorophylls in Bacterial Photosynthetic Reaction Centers from Resonance Raman Intensities

et al. 1997

View full text Add to dashboard Cite

Resonance Raman spectra and absolute Raman scattering intensities of the Franck−Condon coupled vibrational modes of the accessory bacteriochlorophylls (B) in the photosynthetic reaction center from Rb. sphaeroides have been obtained with excitation in their 800 nm Q y absorption band. Although the relative Raman intensities are unchanged when the temperature is reduced from 278 to 95 K, the absolute Raman scattering intensity is found to increase by a factor of ∼4 at 95 K. A self-consistent multimode vibronic model for the excited-state properties of B has been developed that provides a unique fit to the absorption band and the Raman cross sections at both temperatures using a total S (linear electron−nuclear coupling factor) of 0.32 and an effective electronic dephasing time of ∼54 fs at 278 K and ∼210 fs at 95 K. The Raman scattering cross sections are consistent with an electronic structure model where the two B chromophores absorb and scatter independently. The Raman cross sections scale as 1/T 2 in the 95−298 K range, suggesting that the pure dephasing time, if modeled as a Gaussian (slow-modulation limit), decreases linearly with temperature. At room temperature, the electronic dephasing time is controlled by bath-induced dephasing processes rather than the energy transfer time from the excited state of B. The electronic and nuclear relaxation parameters derived here provide a more quantitative picture of the time scale and structural relaxation of the chromophores involved in energy transfer in reaction centers.

show abstract

“…It is well established that certain low-frequency modes in photosynthetic chlorins strongly couple to the lowest-energy optical transition and that these frequencies correspond to those observed in time-domain vibrational coherence spectroscopy [13,14,15,16,17,18,19,20,21,22]. However, the vibronic sidebands observed in electronic spectra correspond to finger-print modes including C=C stretching for the Qx transition, and a 1235 cm −1 mode dominating the Qy excited Resonance Raman of Ni(II) Pheophytin a, which has been assigned to a C–N stretching mode [23]. Likewise, electronic and fluorescence spectroscopy of chlorophyll a finds typical frequencies of 1525 cm −1 and 1145 cm −1 from the vibronic bands [24].…”

Section: Introductionmentioning

confidence: 99%

“…This is an important consideration for the experimental and computational vibrational mode assignments in the literature, considering the frequency position and intensities observed for excited state finger-print modes [27]. The separation and splitting of the Q band into the Qx and Qy transitions result from the effective asymmetry of the chlorophyll structure such that the effective symmetry is C1 [23]. The Franck–Condon analysis of chlorophyll absorption spectra [28] is commonly treated using the Herzberg–Teller effect [26,29].…”

Section: Introductionmentioning

confidence: 99%

Excited State Frequencies of Chlorophyll f and Chlorophyll a and Evaluation of Displacement through Franck-Condon Progression Calculations

Zamzam

Thor

2019

Molecules

View full text Add to dashboard Cite

We present ground and excited state frequency calculations of the recently discovered extremely red-shifted chlorophyll f. We discuss the experimentally available vibrational mode assignments of chlorophyll f and chlorophyll a which are characterised by particularly large downshifts of 131-keto mode in the excited state. The accuracy of excited state frequencies and their displacements are evaluated by the construction of Franck–Condon (FC) and Herzberg–Teller (HT) progressions at the CAM-B3LYP/6-31G(d) level. Results show that while CAM-B3LYP results are improved relative to B3LYP calculations, the displacements and downshifts of high-frequency modes are underestimated still, and that the progressions calculated for low temperature are dominated by low-frequency modes rather than fingerprint modes that are Resonant Raman active.

show abstract

Resonance Raman spectra of and vibronic coupling in Ni(II) pheophytin a

Cited by 9 publications

References 45 publications

Red‐band resonance raman spectroscopy of chlorophyll cofactors in photosynthetic proteins

Red‐band resonance raman spectroscopy of chlorophyll cofactors in photosynthetic proteins

Electronic and Nuclear Dynamics of the Accessory Bacteriochlorophylls in Bacterial Photosynthetic Reaction Centers from Resonance Raman Intensities

Excited State Frequencies of Chlorophyll f and Chlorophyll a and Evaluation of Displacement through Franck-Condon Progression Calculations

Contact Info

Product

Resources

About