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首页> 外文学位 >Monitoring ultrafast evolution of electronic structure within photosynthetic antenna complexes using multidimensional spectroscopies.
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Monitoring ultrafast evolution of electronic structure within photosynthetic antenna complexes using multidimensional spectroscopies.

机译：使用多维光谱学监测光合天线复合物中电子结构的超快演化。

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摘要

Photosynthetic antenna complexes capture solar radiation and transfer the resultant excitation energy to neighboring reaction centers. The quantum efficiency of the excitation energy transfer process in these systems can approach unity at low light intensities. The underlying physical mechanisms that govern the efficiency of this process are not understood. Spectroscopic experiments have revealed that the relaxation process in individual antenna complexes contains a coherent component, whereby the excitation maintains phase information while relaxing. The coherent signatures are manifested as oscillations in signal intensities which are suppressed following photoexcitation due to interaction of the chromophores with the surrounding environment. An understanding of what molecular mechanisms govern the dynamics in these systems could inform design principles for synthetic devices that replicate the efficient dynamics.;The work in this thesis explores the complex underlying physical mechanisms governing the dephasing and relaxation dynamics through the development of spectroscopic and theoretical methodologies. Multidimensional spectroscopic methodologies allow for the elucidation of the mechanism of relaxation and provides insights into high order-correlations present in the protein bath. The time scales of the relaxation dynamics disclose information about the surrounding protein environment, revealing that proteins motions correlate energetic fluctuations following photoexcitation. The rate of dephasing of different coherences can be understood as arising from the interplay of excitonic mixing and spatial proximity of the chromophores. A higher-order multidimensional method is explored to reveal aspects of non-Gaussian dynamics of solvation and vibronic coupling. A nonlinear solvation model is developed to explore the increased sensitivity to molecular details provided by multidimensional methods and can explain what physical parameters lead to non-Gaussian dynamics. Control of the polarization of the excitation pulses allows for different aspects of the relaxation dynamics to be selectively probed. The coherent contributions to the relaxation can selectively be detected revealing the time scales of the dephasing dynamics. Signatures of dynamic localization and supertansfer can be revealed through chiral nonlinear methodologies.
机译：光合天线复合体捕获太阳辐射并将产生的激发能转移到邻近的反应中心。在这些系统中，激发能转移过程的量子效率可以在低光强度下接近统一。尚不清楚控制该过程效率的潜在物理机制。光谱实验表明，单个天线复合体中的弛豫过程包含一个相干分量，从而激发在弛豫时保持相位信息。相干特征表现为信号强度的振荡，由于生色团与周围环境的相互作用，光激发后信号强度受到抑制。了解什么分子机制控制这些系统中的动力学可以为合成装置的设计原理提供参考，该合成装置可以复制有效的动力学。本论文的工作通过光谱学和理论的发展探索了控制相移和弛豫动力学的复杂的基本物理机制。方法论。多维光谱方法可阐明松弛机制，并提供对蛋白质浴中存在的高阶相关性的见解。弛豫动力学的时标揭示了有关周围蛋白质环境的信息，表明蛋白质运动与光激发后的能量波动相关。可以将不同相干的移相速率理解为是由激子混合和生色团的空间邻近性的相互作用引起的。探索了一种高阶多维方法，以揭示溶剂化和振动耦合的非高斯动力学方面。开发了非线性溶剂化模型，以探索多维方法提供的对分子细节的增加的敏感性，并可以解释哪些物理参数导致了非高斯动力学。激励脉冲的极化的控制允许弛豫动力学的不同方面被选择性地探测。可以有选择地检测对松弛的相干贡献，从而揭示相移动力学的时间尺度。可以通过手性非线性方法揭示动态定位和超转移的特征。

著录项

  • 作者

    Fidler, Andrew Francis.;

  • 作者单位

    The University of Chicago.;

  • 授予单位 The University of Chicago.;
  • 学科 Physical chemistry.;Biophysics.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 250 p.
  • 总页数 250
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 宗教;
  • 关键词

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