FINITE PULSE WIDTHS IN TWO-DIMENSIONAL FOURIER TRANSFORM ESR

二维傅里叶变换 ESR 中的有限脉冲宽度

• 批准号: 7956616
• 负责人: ZHICHUN LIANG
• 金额: $ 1.09万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7956616
• 关键词: Affect; Agreement; Complex; Computer Retrieval of Information on Scientific Projects Database; Equation; Fourier Transform; Frequencies; Funding; Grant; Institution; Liquid substance; Membrane; Methods; Peptides; Physiologic pulse; Polymers; Radiation; Research; Research Personnel; Resolution; Resources; Role; Source; Spin Labels; Techniques; Technology; United States National Institutes of Health; Vesicle; Width; base; improved; irradiation; liquid crystal; molecular dynamics; research study; theories; two-dimensional

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Two-dimensional (2D) Fourier Transform ESR techniques, such as 2D-ELDOR, have considerably improved the resolution of ESR in studies of molecular dynamics in complex fluids such as liquid crystals and membrane vesicles and in spin labeled polymers and peptides. A well-developed theory based on the stochastic Liouville equation (SLE) has been successfully employed to analyze these experiments. However, one fundamental assumption has been utilized to simplify the complex analysis, viz. the pulses have been treated as ideal non-selective ones, which therefore provide uniform irradiation of the whole spectrum. In actual experiments, the pulses are of finite width causing deviations from the theoretical predictions, a problem that is exacerbated by experiments performed at higher frequencies. We have developed a method to deal with the full SLE including the explicit role of the molecular dynamics, the spin Hamiltonian and the radiation field during the pulse. The computations are rendered more manageable by utilizing the Trotter formula, which is adapted to handle this SLE in what we call a "Split Super-Operator" method. Examples are given for different motional regimes, which show how 2D-ELDOR spectra are affected by the finite pulse widths. The theory shows good agreement with 2D-ELDOR experiments performed as a function of pulse width.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。列出的机构为 中心，但不一定是研究者所在的机构。 二维（2D）傅立叶变换ESR技术（如2D-ELDOR）在复杂流体（如液晶和膜囊泡）以及自旋标记聚合物和肽的分子动力学研究中显著提高了ESR的分辨率。一个发达的理论的基础上的随机刘维尔方程（SLE）已成功地用来分析这些实验。然而，一个基本的假设已被用来简化复杂的分析，即脉冲已被视为理想的非选择性的，因此提供了整个光谱的均匀照射。在实际的实验中，脉冲是有限宽度的，导致偏离理论预测，在更高频率下进行的实验加剧了这个问题。我们已经发展了一种方法来处理完整的SLE包括明确的作用的分子动力学，自旋哈密顿量和辐射场在脉冲。通过使用Trotter公式，计算变得更易于管理，该公式适用于在我们称为“拆分超级运算符”的方法中处理该SLE。给出了不同的运动制度，这表明如何2D-ELDOR光谱的有限脉冲宽度的影响的例子。该理论显示出良好的协议与2D-ELDOR实验作为脉冲宽度的函数进行。