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Study of relaxation kinetics of excited states in carotenoids and energy transfer in photosynthesis

类胡萝卜素激发态弛豫动力学和光合作用能量转移的研究

基本信息

批准号：
14340089
负责人：
YOSHIZAWA Masayuki
金额：
$ 8.9万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Carotenoids play important roles in light-harvesting (LH) function of photosynthesis. Light energy is initially absorbed by carotenoid and transferred to bacteriochlorophyll with high efficiency. Ultrafast relaxation kinetics of carotenoids has been investigated systematically. Carotenoids with several conjugation lengths and different structures are prepared for the measurements. Their basic optical properties are measured by stationary absorption, fluorescence, and electroabsorption spectroscopies. Femtosecond time-resolved spectroscopy system has been improved and tunable excitation pulses in visible to near-infrared region are utilized. Femtosecond absorption, Raman, and fluorescence spectroscopies have been done under the same excitation condition to compare the results directly.Ultrafast phenomena in carotenoids are summarized as follows. At delay times of nearly equal to zero, nonlinear optical responses in a three-level system of the ground state (1^1A_g^-), the lowest opticall … More y allowed excited state (1^1B_u^+), and a highly excited state (n^1A_g^-) are observed in addition to the signal due to the resonant excitation of 1^1B_u^+. After the generation of 1^1B_u^+, the internal conversion to a lower dark state (2^1A_g^-) occurs with the time constant of 0.1〜0.2 ps. Another dark state (1^1B_u^-) is an intermediate state of the relaxation, but it cannot be time-resolved in this research. Redistribution and dissipation of excess vibrational energy take place simultaneously with the internal conversions. However, some vibrational modes have long lifetimes and 2^1A_g^-remains in vibrational excited levels longer than several picoseconds. The vibrational energy affect the relaxation kinetics and slows down the internal conversions.Preliminary measurement of the LH complex has been done and the experimental system is going to be refined for the study of the vibrational level in the LH complex.This research reveals the main relaxation kinetics of carotenoids and importance of the vibrational levels in the energy transfer from carotenoids to reaction center of the photosynthesis. Less

类胡萝卜素在光合作用的捕光（LH）功能中起着重要作用。光能首先被类胡萝卜素吸收，然后高效地转化为细菌叶绿素。系统地研究了类胡萝卜素的超快弛豫动力学。制备了具有几种共轭长度和不同结构的类胡萝卜素用于测量。它们的基本光学性质是通过静态吸收，荧光和电吸收光谱测量的。对飞秒时间分辨光谱系统进行了改进，采用了可见-近红外波段可调谐的激发脉冲。在相同的激发条件下进行了飞秒吸收、拉曼和荧光光谱的测试，以直接比较结果。在延迟时间几乎等于零时，基态（1^1A_g^-）的三能级系统的非线性光学响应是最低的。 ...更多信息除了1^1B_u^+的共振激发信号外，还观察到一个高激发态（n^1A_g^-）。在产生1^1B_u^+后，发生了向较低暗态（2^1A_g^-）的内部转换，时间常数为0.1 ~ 0.2 ps。另一个暗态（1^1B_u^-）是弛豫的中间态，但在本研究中不能进行时间分辨。多余振动能的重新分配和消散与内部转换同时发生。然而，一些振动模式具有较长的寿命，并且2^1A_g^-保持在振动激发能级上的时间超过几皮秒。振动能影响弛豫动力学，减缓了光合作用的内部转化，对LH复合物进行了初步测量，并对LH复合物振动能级的研究进行了改进，揭示了类胡萝卜素的主要弛豫动力学，以及振动能级在类胡萝卜素向光合作用反应中心的能量传递中的重要性。少

项目成果

期刊论文数量（81）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Time-resolved Absorption and Fluorescence Spectroscopy in Carotenoids Using Tunable Femtosecond Pump Pulses

使用可调谐飞秒泵脉冲对类胡萝卜素进行时间分辨吸收和荧光光谱分析

DOI：
发表时间：
2005
期刊：
Carotenoid Science 8
影响因子：
0
作者：
T.Buckup et al.;W.Wohlleben et al.;K.Yanagi et al.;K.Yanagi et al.;K.Kanemoto et al.;D.Kosumi et al.;I.Akai et al.;M.Yoshizawa et al.;T.Buckup et al.;G.Cerullo et al.;P.Wang et al.;T.Nishio et al.;M.Sugisaki et al.;K.Yanagi et al.;R.Fujii et al.;D.Kosumi et al.
通讯作者：
D.Kosumi et al.

H.Hashimoto, T.Yoda, T.Kobayashi, A.J.Young: "Molecular Structures of Carotenoids as Predicted by MNDO-AMl Molecular Orbital Calculations"J. Mol. Struct.. 604. 125-146 (2002)

H.Hashimoto、T.Yoda、T.Kobayashi、A.J.Young：“通过 MNDO-AM1 分子轨道计算预测类胡萝卜素的分子结构”J。