How do surrounding environments influence the electronic and vibrational properties of spheroidene?
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Absorption and Raman spectra of spheroidene dissolved in various organic solvents and bound to peripheral light-harvesting LH2 complexes from photosynthetic purple bacteria Rhodobacter (Rba.) sphaeroides 2.4.1 were measured. The results showed that the peak energies of absorption and C–C and C=C stretching Raman lines are linearly proportional to the polarizability of solvents, as has already been reported. When comparing these results with those measured on LH2 complexes, it was confirmed that spheroidene is surrounded by a media with high polarizability. However, the change in the spectral width of the Raman lines, which reflect vibrational decay time, cannot be explained simply by a similar dependence of solvent polarizability. The experimental results were analyzed using a potential theoretical model. Consequently, a systematic change in the Raman line widths in the ground state can be satisfactorily explained as a function of the viscosity of the surrounding media. Even when the absorption peaks appear at the same energy, the vibrational decay time of spheroidene in the LH2 complexes is approximately 15–20 % slower than that in organic solvents.
KeywordsCarotenoid LH2 Raman spectroscopy Vibrational decay Polarizability Viscosity
Density functional theory
Half-width at half-maximum
This work was conducted with financial support from the Grant-in-aid from the Japanese Ministry of Education, Culture, Sports, Science, and Technology (Grants No. 22340085 and No. 26610133). HH thanks Scientific Research on Innovative Area “All Nippon Artificial Photosynthesis Project for Living Earth (AnApple)” (No. 24107002H) from the Japan Society for the Promotion of Science (JSPS) for financial support.
- Frank HA, Bautista JA, Josue J, Pendon Z, Hiller RG, Sharples FP, Gosztola D, Wasielewski MR (2000) Effect of the solvent environment on the spectroscopic properties and dynamics of the lowest excited states of carotenoids. J Phys Chem B 104(18):4569–4577. doi: 10.1021/jp000079u CrossRefGoogle Scholar
- Fujiwara M, Yamauchi K, Sugisaki M, Gall A, Robert B, Cogdell RJ, Hashimoto H (2008) Energy dissipation in the ground-state vibrational manifolds of β-carotene homologues: a sub-20-fs time-resolved transient grating spectroscopic study. Phys Rev B 77:205118. doi: 10.1103/PhysRevB.77.205118 CrossRefGoogle Scholar
- Kok P, Köhler J, Groenen EJJ, Gebhard R, van der Hoef I, Lugtenburg J, Hoff AJ, Farhoosh R, Frank HA (1994) Towards a vibrational analysis of spheroidene—resonance Raman spectroscopy of 13C-labeled spheroidenes in petroleum ether and in the Rhodobacter sphaeroides reaction center. Biochim Biophys Acta Bioenerg 1185(2):188–192. doi: 10.1016/0005-2728(94)90209-7 CrossRefGoogle Scholar
- Kosumi D, Fujiwara M, Fujii R, Cogdell RJ, Hashimoto H, Yoshizawa M (2009a) The dependence of the ultrafast relaxation kinetics of the S2 and S1 states in beta-carotene homologs and lycopene on conjugation length studied by femtosecond time-resolved absorption and Kerr-gate fluorescence spectroscopies. J Chem Phys 130(21):214506. doi: 10.1063/1.3147008 CrossRefPubMedGoogle Scholar
- Kosumi D, Kusumoto T, Fujii R, Sugisaki M, Iinuma Y, Oka N, Takaesu Y, Taira T, Iha M, Frank HA, Hashimoto H (2009b) One- and two-photon pump-probe optical spectroscopic measurements reveal the S1 and intramolecular charge transfer states are distinct in fucoxanthin. Chem Phys Lett 483(1–3):95–100. doi: 10.1016/j.cplett.2009.10.077 CrossRefGoogle Scholar
- Kuki M, Nagae H, Cogdell RJ, Shimada K, Koyama Y (1994) Solvent effect on spheroidene in nonpolar and polar solutions and the environment of spheroidene in the light-harvesting complexes of Rhodobacter sphaeroides 2.4.1 as revealed by the energy of the 1Ag−→1Bu+ absorption and the frequencies of the vibronically coupled C=C stretching Raman lines in the 1Ag− and 21Ag− states. Photochem Photobiol 59(1):116–124. doi: 10.1111/j.1751-1097.1994.tb05009.x CrossRefGoogle Scholar
- Mukai-Kuroda Y, Fujii R, Ko-chi N, Sashima T, Koyama Y (2002) Changes in molecular structure upon triplet excitation of all-trans-spheroidene in n-hexane solution and 15-cis-spheroidene bound to the photo-reaction center from Rhodobacter sphaeroides as revealed by resonance-Raman spectroscopy and normal-coordinate analysis. J Phys Chem A 106(14):3566–3579. doi: 10.1021/jp0130822 CrossRefGoogle Scholar
- Ostroumov EE, Khan YR, Scholes GD, Govindjee (2014) Photophysics of potosynthetic pigment-protein complexes. In: Demmig-Adams B, Garab G, Adams W III, Govindjee (eds) Non-photochemical quenching and energy dissipation in plants, algae and cyanobacteria. Advances in photosynthesis and respiration, including bioenergy and related processes, vol 40. Springer, Dordrecht, pp 97–128Google Scholar
- Parson WW (2006) Modern optical spectroscopy: with examples from biophysics and biochemistry. Springer-Verlag, BerlinGoogle Scholar
- Rondonuwu FS, Watanabe Y, Fujii R, Koyama Y (2003) A first detection of singlet to triplet conversion from the 11Bu− to the 13Ag state and triplet internal conversion from the 13Ag to the 13Bu state in carotenoids: dependence on the conjugation length. Chem Phys Lett 376(3–4):292–301. doi: 10.1016/s0009-2614(03)00983-7 CrossRefGoogle Scholar
- Rondonuwu FS, Yokoyama K, Fujii R, Koyama Y, Cogdell RJ, Watanabe Y (2004) The role of the 11Bu− state in carotenoid-to-bacteriochlorophyll singlet-energy transfer in the LH2 antenna complexes from Rhodobacter sphaeroides G1C, Rhodobacter sphaeroides 2.4.1, Rhodospirillum molischianum and Rhodopseudomonas acidophila. Chem Phys Lett 390(4–6):314–322. doi: 10.1016/j.cplett.2004.03.089 CrossRefGoogle Scholar
- Sakamoto A, Matsuno S, Tasumi M (2010) Picosecond near-infrared excited transient Raman spectra of beta-carotene in the excited S2 state: solvent effects on the in-phase C=C stretching band and vibronic coupling. J Mol Struct 976(1–3):310–313. doi: 10.1016/j.molstruc.2010.04.012 CrossRefGoogle Scholar
- Sugisaki M, Fujiwara M, Kosumi D, Fujii R, Nango M, Cogdell RJ, Hashimoto H (2010) Comparison of transient grating signals from spheroidene in an organic solvent and in pigment-protein complexes from Rhodobacter sphaeroides 2.4.1. Phys Rev B 81(20):245112. doi: 10.1103/PhysRevB.80.035118 CrossRefGoogle Scholar