Chiral Molecular Beams, Quantum Tunneling and Improved Microwave Spectroscopy

化学系化学测量和成像计划获得这一奖项，支持哈佛大学的John Doyle教授通过分子束技术的进步和微波光谱学的询问来研究分子手性。原子和分子是所有物质的基本构件。为了充分理解化学过程，包括那些潜在的生命系统，了解它们的基本行为是必要的。在活细胞中，许多分子有一个基本的“扭曲”，非常类似于螺丝上螺旋脊的方向。就像螺丝一样，分子螺旋的方向，也就是所谓的“手性”，决定了功能。对于普通的螺丝(“右手”螺丝)，如果你顺时针旋转它们，它们就会拧紧；“左手”螺丝就会松动。这在分子中也是一个非常明显的效应。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。在这个项目中，研究人员将使用他们新发现的手性测量工具来研究分子中手性的基本量子行为。特别是，他们将寻找一个在一个方向上有螺旋的分子到一个在相反方向上有螺旋的分子的缓慢转变。这种效应只能用微观领域的基本理论--量子力学来描述。多伊尔小组的研究人员将检验这些预测，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，多伊尔小组将使用分子束，并用微波辐射进行询问。分子缝将通过一个小孔注入到近乎完美的真空中，从而产生分子缝。这将形成一个分子流，除了外加的电磁辐射外，这些分子没有任何相互作用，几乎是原始的物理结构。将要研究的分子具有电偶极子(类似于条形磁铁，不同之处在于北极和南极带有电荷)。这些偶极子将在微波区域吸收和发射辐射。通过创建螺杆式的微波辐射模式，可以使分子发射依赖于分子螺旋方向(手性)的辐射。这类似于通过尝试将螺丝插入右手螺丝孔来测试螺丝是左手还是右手。研究人员将首先制备一种手性(例如右手)的分子，然后使用微波观察它们是否会转变为另一种手性(左手)。为了检验我们对这一基本现象的理解，我们将进行理论比较。

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.