Chiral Interferometry and Density Functional Theory of Magnetic Responses

加州大学伯克利分校的罗伯特·哈里斯教授得到了理论与计算化学项目的资助，继续他在两个不同领域的研究。前者研究手性分子叠加态的存在，而后者研究分子中的磁响应。量子力学的一个基本结论是手性分子的叠加态的存在。直到最近，还没有关于如何制备这些基本量子物体的建议。哈里斯最近提出了一个关于如何准备叠加和评估其相干性的基本理论。本研究的目的之一是概括这些连贯性的概念，并构建更现实和多样化的方法来准备和测量它们。鉴于它们在各种条件下的产生，建议研究这些叠加的行为。特别是，PI将研究它们如何与其他系统碰撞，以及它们在凝聚态物质中的相干性如何降低。最后，手性的旋转相干也将被研究。第二个领域涉及分子系统中的磁响应，历史上包括分别计算抗磁和顺磁贡献。最近提出的磁场密度泛函理论强调，密度泛函理论原则上允许自动构造规范不变量理论。此外，在没有磁场的情况下，所有的响应都是电子密度的泛函。将进行磁响应的计算。此外，一个理论的变化，电子密度的变化，由于遥远的基团和它们与磁响应的关系，将被构建。这项工作的第一个方面涉及手性分子叠加的存在，这是量子力学的一个基本结果。直到最近，还没有关于如何制备这些基本量子物体的建议。PI和他的同事J.Cina最近提出了一个关于如何制备叠加和评估其相干性的基本理论。在即将开展的工作中，将为实际分子建立一个详细的理论，以便进行实验。第二个目的是为了了解激发态光化学，这是叠加的结果，与普通手性分子和这些分子的混合物有什么不同。这项工作的第二个方面涉及核磁共振。（NMR）用于确定各种分子和更复杂的系统（如蛋白质和RNA）的结构。这些结构的评价是基于系统的核磁共振参数随几何形状和环境变化的变化。提出了一种基于PI的系统计算核磁共振参数的新方法。该方法基于系统的电子密度，以及它如何随几何形状和环境而变化。这种观察核磁共振参数的方法没有先例，应该对电子密度本身的构造有用。

Professor Robert Harris of the University of California, Berkeley is being supported by a grant from the Theoretical and Computational Chemistry Program to continue his research in two distinct areas. The first deals with the existence of superpositions of handed molecules, while the second deals with magnetic responses in molecules. A basic consequence of quantum mechanics is the existence of superpositions of handed molecules. Until recently there were no suggestions as to how to prepare these fundamentally quantum objects. Harris has very recently advanced an elementary theory of how the superpositions may be prepared, and their coherence assessed. One purpose of the proposed research is to generalize both the idea of these coherences and construct more realistic and varied ways of preparing and measuring them. Given their production in a variety of conditions, it is proposed to investigate the behavior of these superpositions. In particular, the PI will examine how they collide with other systems, as well as how their coherence degrades in condensed matter. Finally, rotational coherences which are chiral will also be investigated. The second area involves magnetic responses in molecular systems which historically involves calculating diamagnetic and paramagnetic contributions separately. A recently proposed magnetic field density functional theory emphasizes that density functional theory allows, in principle, a gauge invariant theory to be automatically constructed. In addition, all responses are universal functionals of the electron density in the absence of magnetic fields. Calculations of magnetic responses will be carried out. In addition, a theory of changes in electron density due to distant groups and their relation to magnetic responses, will be constructed. The first aspect of this work deals with the existence of superpositions of handed molecules, which arrises as a basic consequence of quantum mechanics. Until recently there were no suggestions as to how to prepare these fundamentally quantum objects. The PI and his colleague J.Cina, have very recently advanced an elementary theory of how the superpositions may be prepared, and their coherence assessed. In work to be carried out, a detailed theory will be constructed for real molecules so that experiments may be carried out. A second purpose is to see how the excited state photochemistry, which is a consequence of the superpositions, differs from that of ordinary handed molecules and mixtures of those molecules. The second aspect of this work deals with Nuclear Magnetic Resonance. (NMR) is used to determine the structure of a variety of molecules and more complex systems such as proteins and RNA. The assessment of these structures is based on the variation of the NMR parameters of the system with changes in geometry and environment. The research proposed is based on a new method by the PI for calculating in a systematic way the NMR parameters. The method is based on the electron density of the system, and how it changes with geometry and environs. This way of looking at NMR parameters has no precedent and should be useful in the construction of the electron density itself.