Molecular theories of electronic energy transfer dynamics and their environmental regulation in photosynthetic light harvesting systems

2017 Fiscal Year Final Research Report

• Project/Area Number: 25708003
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Physical chemistry
• Research Institution: Institute for Molecular Science
• Principal Investigator: Ishizaki Akihito 分子科学研究所, 理論・計算分子科学研究領域, 教授 (60636207)
• Project Period (FY): 2013-04-01 – 2018-03-31
• Keywords: 量子動力学 / 光合成初期過程 / 電子エネルギー移動 / 電荷分離反応

Outline of Final Research Achievements

Photosynthetic energy conversion starts with charge separation (CS) in the reaction center (RC) protein. In particular, oxygenic photosynthesis in plants begins in photosystem II (PSII) RC. We comprehensively investigated impacts of the protein environment and intramolecular vibrational modes on the primary CS processes in the PSII-RC by combining quantum dynamic theories of condensed phase electron transfer reaction with quantum chemical calculations for evaluating the vibrational Huang-Rhys factors. We revealed that individual vibrational modes play a minor role in promoting the CS, contrary to the discussion in recent publications. However, such small contributions add up to make a big change of the CS rate, resulting in sub-picosecond CS almost independent of values of the driving force. The intramolecular vibrations maintain robustness of the CS in the PSII-RC against inherently large static disorder of the electronic energies of the electron donor and acceptor states.

Free Research Field

物理化学、化学物理、量子散逸系