期刊
JOURNAL OF CHEMICAL PHYSICS
卷 147, 期 13, 页码 -出版社
AMER INST PHYSICS
DOI: 10.1063/1.4999057
关键词
-
资金
- MRSEC [DMR 14-20709]
- AFOSR [FA9550-14-1-0367]
- DoD Vannevar Bush Fellowship [N00014-16-1-2513]
- Camille and Henry Dreyfus Foundation
- Sloan Foundation
- DoD, Air Force Office of Scientific Research, National Defense Science and Engineering Graduate (NDSEG) Fellowship [32 CFR 168a]
- NSF-GRFP program
- National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health [T32-EB009412]
- Yen Fellowship at UChicago
- Arnold and Mabel Beckman Foundation
- Biotechnology and Biological Sciences Research Council (UK) [BB/M000265/1]
- European Research Council [338895]
- Photosynthetic Antenna Research Center (PARC), an Energy Frontier Research Center - U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-SC 0001035]
- BBSRC [BB/M000265/1] Funding Source: UKRI
- Biotechnology and Biological Sciences Research Council [BB/M000265/1] Funding Source: researchfish
In photosynthetic organisms, the pigment-protein complexes that comprise the light-harvesting antenna exhibit complex electronic structures and ultrafast dynamics due to the coupling among the chromophores. Here, we present absorptive two-dimensional (2D) electronic spectra from living cultures of the purple bacterium, Rhodobacter sphaeroides, acquired using gradient assisted photon echo spectroscopy. Diagonal slices through the 2D lineshape of the LH1 stimulated emission/ground state bleach feature reveal a resolvable higher energy population within the B875 manifold. The waiting time evolution of diagonal, horizontal, and vertical slices through the 2D lineshape shows a sub-100 fs intra-complex relaxation as this higher energy population red shifts. The absorption (855 nm) of this higher lying sub-population of B875 before it has red shifted optimizes spectral overlap between the LH1 B875 band and the B850 band of LH2. Access to an energetically broad distribution of excitonic states within B875 offers a mechanism for efficient energy transfer from LH2 to LH1 during photosynthesis while limiting back transfer. Two-dimensional lineshapes reveal a rapid decay in the ground-state bleach/stimulated emission of B875. This signal, identified as a decrease in the dipole strength of a strong transition in LH1 on the red side of the B875 band, is assigned to the rapid localization of an initially delocalized exciton state, a dephasing process that frustrates back transfer from LH1 to LH2. Published by AIP Publishing.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据