论文标题
无序分子培养基的硬X射线螺旋二分性
Hard X-ray helical dichroism of disordered molecular media
论文作者
论文摘要
手性是缺乏镜子对称性的分子的结构特性，在不同领域具有强烈影响，从生活到材料科学。对手性敏感的建立光谱法（例如圆形二色性（CD））在ACHIRAL背景上表现出弱信号贡献。基于光轨道动量（OAM）的螺旋二色性（HD）提供了一种新的方法来探测分子手性的方法，但从未在无序的样品上证明它。此外，在光学域中，挑战在于需要将光子的OAM转移到位于ÅSize轨道上的电子中。在这里，我们使用带有螺旋菲涅尔区的硬X射线克服了这一挑战，这可能会诱导绿月。我们介绍了[Fe（4,4'-dimebpy）3] 2+在铁k-边缘（7.1 keV）的对映射分子复合物的无序粉末样品的第一个HD光谱，并带有OAM携带梁。高清光谱显示出从左侧螺旋波前或从对映异构体转到另一个的符号的预期反转。 HD光谱的不对称比在一到三个的绿色光束范围内为1-5％。这些结果为研究分子性手性研究及其与光角动量的相互作用打开了新的窗口。
Chirality is a structural property of molecules lacking mirror symmetry that has strong implications in diverse fields, ranging from life to materials sciences. Established spectroscopic methods that are sensitive to chirality, such as circular dichroism (CD), exhibit weak signal contributions on an achiral background. Helical dichroism (HD), which is based on the orbital angular momentum (OAM) of light, offers a new approach to probe molecular chirality, but it has never been demonstrated on disordered samples. Furthermore, in the optical domain the challenge lies in the need to transfer the OAM of the photon to an electron that is localized on an Å-size orbital. Here, we overcome this challenge using hard X-rays with spiral Fresnel zone, which can induce an OAM. We present the first HD spectra of a disordered powder sample of enantiopure molecular complexes of [Fe(4,4'-diMebpy)3]2+ at the iron K-edge (7.1 keV) with OAM-carrying beams. The HD spectra exhibit the expected inversions of signs switching from a left to a right helical wave front or from an enantiomer to the other. The asymmetry ratios for the HD spectra are within one to five percent for OAM beams with topological charges of one and three. These results open a new window into the studies of molecular chirality and its interaction with the orbital angular momentum of light.
