Univ. Grenoble Alpes, Grenoble 38000, France; CEA, Leti, Minatec Campus, Grenoble 38054, France; CNRS, Institut Néel, Grenoble 38042, France; ETSF, Nano-Bio-Pharma Spectroscopy group, Grenoble 38000, France.
Univ. Grenoble Alpes, Grenoble 38000, France; CNRS, Institut Néel, Grenoble 38042, France; ETSF, Nano-Bio-Pharma Spectroscopy group, Grenoble 38000, France.
J Photochem Photobiol B. 2022 Jul;232:112475. doi: 10.1016/j.jphotobiol.2022.112475. Epub 2022 May 20.
The photo-absorption process and the excitation of chlorophyll (Chl) is the primary and essential step of photosynthesis in green plants. By solving the Bethe-Salpeter equation (BSE) on top of the GW approximation within ab initio many-body perturbation theory, we calculate the photo-absorption function and the excitons structure of Chl a and b in their in vivo conformations as measured by X-ray diffraction in the light-harvesting complex (LHC) II. BSE optical absorption spectra are in good agreement with the experiment and we discuss residual discrepancies. The experimental evidence of multiple Chla forms in vivo is explained by BSE. The Chla and Chlb BSE exciton wavefunctions present important charge-transfer differences on the Soret band. Q excitons are almost identical, apart from charge (both electron and hole) localization on the Chlb C7 aldheide formyl group, absent on the Chla methyl C7, that is exactly the group where the two chlorophylls differ.
光吸收过程和叶绿素（Chl）的激发是绿色植物光合作用的首要和基本步骤。通过在从头算多体微扰理论中GW 近似之上求解 Bethe-Salpeter 方程（BSE），我们计算了在光收集复合物（ LHC） II 中通过 X 射线衍射测量的 Chl a 和 b 在其体内构象中的光吸收函数和激子结构。BSE 光吸收光谱与实验吻合良好，我们讨论了剩余的差异。BSE 解释了体内存在多种 Chla 形式的实验证据。Chla 和 Chlb BSE 激子波函数在 Soret 带呈现出重要的电荷转移差异。Q 激子几乎完全相同，除了 Chlb C7 aldheide 甲酰基团上的电荷（电子和空穴）定位，而 Chla 甲基 C7 上没有，而正是这两个叶绿素不同的基团。
