利用飞秒宽带荧光光谱仪揭示光合细菌反应中心原初过程  

Primary Processes in Bacterial Reaction Center Revealed by Femtosecond Broadband Fluorescence Spectroscopy

作　　者：刘鹤元 甄张赫 彭凌峰 陈海龙[1,2,3] 翁羽翔 Heyuan Liu;Zhanghe Zhen;Lingfeng Peng;Hailong Chen;Yu-Xiang Weng(The Laboratory of Soft Matter Physics,Bejing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;School of Physical Science,University of the Chinese Academy of Sciences,Beijing 100049,China;Songshan LakeMaterials Laboratory,Dongguan 523808,China)

机构地区：[1]中国科学院物理研究所软物质物理实验室,北京100190 [2]中国科学院大学物理学院,北京100049 [3]松山湖材料实验室,东莞523808

出　　处：《Chinese Journal of Chemical Physics》2023年第6期655-663,I0055,共10页化学物理学报（英文）

基　　金：financially supported by the National Key Research and Development Program of China(No.2021YFA1201500);the National Natural Science Foundation of China(No.22027802,No.22222308);the CAS project for Young Scientists and Basic Research(No.YSBR-007);the Natural Science Foundation of Shandong Province(No.ZR2021LLZ003);the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB33000000).

摘　　要：本文为深入了解光合细菌反应中心内的高效能量转换机制,采用飞秒宽带荧光光谱技术,研究了室温下光合细菌反应中心中光诱导能量转移和电荷分离的动力学过程.得益于此技术的宽带光谱测量能力,直接确认了与细菌叶绿素B和P相关的两种不同的瞬态荧光组分,其Stokes位移分别确定为约197和450cm^(-1).通过对荧光发射动力学的拟合,揭示了从细菌脱镁叶绿素H到细菌叶绿素B(98 fs)和从细菌叶绿素B到细菌叶绿素P(170 fs)的超快能量转移过程.值得注意的是,预期亚200 fs的细菌叶绿素B荧光寿命被显著延长至约400 fs,表明B的电子激发态与P的电子振动态之间可能存在一-定的耦合,并对能量转移过程有潜在的促进作用.上述发现将有助于人们进一步理解电子振动耦合动力学对光合反应中心内光诱导原初过程的影响机制.To gain a deeper understanding of the highly efficient mechanisms within the photosynthetic bacterial reaction center(BRC),we have employed femtosecond broadband fluorescence spectroscopy to investigate the dynamics of initial photo-induced energy transfer and charge separation in BRC at room temperature.Benefiting from the broadband spectral coverage inherent of this technique,two distinct transient emission species associated with bacteriochlorophylls B and P are directly identified,with Stokes shifts determined to be~197 and 450 cm^(−1),respectively.The ultrafast energy transfers from bacteriopheophytin H to B(98 fs)and from B to P(170 fs)are unveiled through fitting the emission dynamics.Notably,the anticipated sub-200 fs lifetime of B emission significantly extends to~400 fs,suggesting a plausible coupling between the electronic excited state of Band the vibronic states of P,potentially influencing the acceleration of the energy transfer process.These findings should pave the way for understanding the impact of vibronic dynamics on the photo-induced primary processes in the photosynthetic reaction center.

关 键 词：细菌反应中心 飞秒宽带荧光光谱仪 能量转移 电荷分离 瞬态荧光 

分 类 号：O657.3[理学—分析化学] Q935[理学—化学]