Spectroscopic Studies of the Low-Lying Singlet Excited Electronic States and Photochemical Properties of Carotenoids

Frank, Harry A.

doi:10.1006/abbi.2000.2091

Cited by 38 publications

(28 citation statements)

References 58 publications

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“…97 Formally, ␤-carotene has 11 double bonds in the polyene backbone, but by comparing the excitation energies of the polyenes with our ␤-carotene excitation energies, we can estimate a reduced conjugation length of 9.5-9.7 bonds, which is very close to the experimental estimate of 9.7 of Onaka et al 71 ͑Fig. 7͒.…”

Section: Discussionsupporting

confidence: 71%

Orbital optimization in the density matrix renormalization group, with applications to polyenes and β-carotene

Ghosh¹,

Hachmann²,

Yanai³

et al. 2008

The Journal of Chemical Physics

356

447

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In previous work we have shown that the density matrix renormalization group ͑DMRG͒ enables near-exact calculations in active spaces much larger than are possible with traditional complete active space algorithms. Here, we implement orbital optimization with the DMRG to further allow the self-consistent improvement of the active orbitals, as is done in the complete active space self-consistent field ͑CASSCF͒ method. We use our resulting DMRG-CASSCF method to study the low-lying excited states of the all-trans polyenes up to C 24 H 26 as well as ␤-carotene, correlating with near-exact accuracy the optimized complete -valence space with up to 24 active electrons and orbitals, and analyze our results in the light of the recent discovery from resonance Raman experiments of new optically dark states in the spectrum.

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Section: Discussionsupporting

confidence: 71%

Orbital optimization in the density matrix renormalization group, with applications to polyenes and β-carotene

Ghosh¹,

Hachmann²,

Yanai³

et al. 2008

The Journal of Chemical Physics

356

447

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“…Computational analysis Geometry and excited singlet state level ordering Long-chain linear polyenes have low-lying forbidden 2 1 A À g excited singlet states (Christensen 1999;Frank 2001;Christensen et al 2004). Our calculations support this assignment for the spheroidene molecules when the ground state geometry is generated using high-level theory.…”

Section: 12-locked-cis-spheroidenementioning

confidence: 99%

Stereoisomers of Carotenoids: Spectroscopic Properties of Locked and Unlocked cis-isomers of Spheroidene

et al. 2005

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A systematic optical spectroscopic and computational investigation of a series of locked-cis-isomers of spheroidene has been carried out with the goal being to better understand the relationships between stereochemistry, photochemistry, photophysics and biological function of geometric isomers of carotenoids. The spectroscopic properties of 15,15'-locked-cis-spheroidene, 13,14-locked-cis-spheroidene, 11, 12-locked-cis-spheroidene in solution are compared with those observed for unlocked spheroidene. The locked-cis bonds are incapable of undergoing cis-to-trans isomerization and therefore provide an effective means of exploring the relationship between specific stereoisomers and molecular spectroscopy. Samples of the molecules were purified using a high performance liquid chromatography (HPLC) apparatus equipped with a diode array detector, which records the absorption spectra immediately as the molecules emerge from the column and prior to any isomerization that might occur. For several stable isomers, resonance Raman (rR) spectroscopy was carried out to assign their configurations. Quantum computations of absorption spectra were performed using ZINDO/S and also MNDO-PSDCI methods employing nearly full single and double configuration interaction within the pi-electron manifold. Also, for a few test cases, ground state minimizations were done using density functional methods (B3LYP/6-31G(d)). The MNDO-PSDCI methods coupled with the density functional ground state minimization provide an accurate assignment of the positions of the 2(1)Ag - , 1(1)Bu +, and 1(1)Ag + excited states and also address the nature of the forbidden 1(1)Bu - state, whose location is uncertain for polyenes and carotenoids. We demonstrate that the configurational description of the 1(1)Bu - state is sufficiently unique to preclude assignment of its energy based on the characterization of surrounding excited singlet states. The experimental and computational data also offer important insights into the photochemical and photophysical properties of stereoisomers of carotenoids.

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“…The lowest optically active state is the 1 1 B u + (S 2 ) state. The photogenerated 1 1 B u + state converts to the 2 1 A g − state within 100-300 fs and the lifetime of the 2 1 A g − state is several picoseconds [6]. In the light-harvesting pigment-protein complexes in purple photosynthetic bacteria singlet-singlet energy transfer from both of these singlet excited-states to bacteriochlorophyll (BChl) molecules was identified based on the research using sub-picosecond time-resolved fluorescence spectroscopy [7].…”

Section: Introductionmentioning

confidence: 99%

Ultrafast time-resolved vibrational spectroscopies of carotenoids in photosynthesis

Hashimoto

Sugisaki

Yoshizawa

2015

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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This review discusses the application of time-resolved vibrational spectroscopies to the studies of carotenoids in photosynthesis. The focus is on the ultrafast time regime and the study of photophysics and photochemistry of carotenoids by femtosecond time-resolved stimulated Raman and four-wave mixing spectroscopies. This article is part of a Special Issue entitled: Vibrational spectroscopies and bioenergetic systems.

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Spectroscopic Studies of the Low-Lying Singlet Excited Electronic States and Photochemical Properties of Carotenoids

Cited by 38 publications

References 58 publications

Orbital optimization in the density matrix renormalization group, with applications to polyenes and β-carotene

Orbital optimization in the density matrix renormalization group, with applications to polyenes and β-carotene

Stereoisomers of Carotenoids: Spectroscopic Properties of Locked and Unlocked cis-isomers of Spheroidene

Ultrafast time-resolved vibrational spectroscopies of carotenoids in photosynthesis

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