Chiral Molecular Beams, Quantum Tunneling and Improved Microwave Spectroscopy

手性分子束、量子隧道和改进的微波光谱

• 批准号: 1506868
• 负责人: John Doyle
• 金额: $ 45万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1506868&HistoricalAwards=false
• 关键词: Chiral; Molecular; Beams; Quantum; Tunneling

With this award, the Chemical Measurement and Imaging Program of the Division of Chemistry is supporting Professor John Doyle of Harvard University to study molecular chirality through advances in molecular beam techniques and interrogation with microwave spectroscopy. Atoms and molecules are the basic building blocks of all substances. Understanding their essential behavior is necessary for a full understanding of chemical processes, including those underlying living systems. In living cells, many molecules have a fundamental 'twist', very similar to the direction of spiral ridges on a screw. Just like a screw, the direction of the molecular spiral, known as 'chirality', determines function. For normal screws ('right handed' ones), if you turn them clockwise they tighten; a 'left handed' screw would loosen. This is a very pronounced effect in molecules also. For example, many new drugs have a single handedness (i.e. chirality). In order to understand the basic behavior of molecules, their chirality must be detectable. In this project researchers will use their newly discovered tool for measuring chirality to study fundamental quantum behavior of chirality in molecules. In particular, they will look for the slow transformation of a molecule with a spiral in one direction to a molecule with a spiral in the opposite direction. This effect can only be described by the fundamental theory of the microscopic realm, quantum mechanics. Researchers in the Doyle group will test these predictions and in carrying out these studies gain valuable experience in modern physical and analytical chemistry research.In order to study chirality of molecules, the Doyle group will use molecular beams and interrogate these with microwave radiation. The molecular seams will be generated by injecting them through a small hole into a nearly perfect vacuum. This will form a stream of molecules that have no interactions 'a nearly pristine physical setup' except with the applied electromagnetic radiation. The molecules that will be studied have electric dipoles (similar to a bar magnet, except with electric charge on the North and South poles). These dipoles will absorb and emit radiation in the microwave regime. By creating a screw-type pattern of microwave radiation, the molecule can be caused to emit radiation that depends on the direction of the spiral (chirality) of the molecules. This is similar to testing if a screw is left or right handed by trying to insert it in a right-handed screw hole. The researchers will initially prepare molecules of one chirality (e.g. right handed) and then use microwaves to see if they transform into the other chirality (left-handed). Comparison with theory will be done to test our understanding of this fundamental phenomenon.

凭借该奖项，化学系的化学测量和成像项目正在支持哈佛大学的约翰·道尔教授通过分子束技术和微波光谱分析的进步来研究分子手性。 原子和分子是所有物质的基本组成部分。了解它们的基本行为对于充分理解化学过程（包括那些潜在的生命系统）是必要的。在活细胞中，许多分子具有基本的“扭曲”，与螺钉上螺旋脊的方向非常相似。就像螺丝一样，分子螺旋的方向（称为“手性”）决定了功能。对于普通螺钉（“右手”螺钉），如果顺时针旋转，它们就会拧紧； “左手”螺丝会松动。这在分子中也是非常明显的效应。例如，许多新药具有单手性（即手性）。为了了解分子的基本行为，它们的手性必须是可检测的。在该项目中，研究人员将使用他们新发现的测量手性的工具来研究分子中手性的基本量子行为。特别是，他们将寻找具有一个方向的螺旋的分子缓慢转变为具有相反方向的螺旋的分子。这种效应只能用微观领域的基础理论——量子力学来描述。道尔小组的研究人员将测试这些预测，并在进行这些研究的过程中获得现代物理和分析化学研究的宝贵经验。为了研究分子的手性，道尔小组将使用分子束并用微波辐射来询问它们。分子接缝将通过将它们通过小孔注入近乎完美的真空中来产生。这将形成分子流，除了与施加的电磁辐射之外，分子流没有相互作用，“几乎原始的物理设置”。将研究的分子具有电偶极子（类似于条形磁铁，除了北极和南极上有电荷）。这些偶极子将吸收和发射微波范围内的辐射。通过创建微波辐射的螺旋型图案，可以使分子发射取决于分子螺旋方向（手性）的辐射。这类似于通过尝试将螺钉插入右旋螺钉孔来测试螺钉是左旋还是右旋。研究人员将首先制备一种手性分子（例如右手性分子），然后使用微波观察它们是否会转变为另一种手性分子（左手性分子）。将与理论进行比较，以检验我们对这一基本现象的理解。