Creating, imaging, and controlling dynamic chirality induced by molecular rotations

手性在自然界中无处不在，通常与两种对映体（镜像）形式的分子的化学或光学活性有关。自从路易斯·巴斯德于1848年发现手性以来，关于手性的起源仍然存在许多悬而未决的问题。值得注意的是，生物分子（homo）手性的起源是一个有争议的话题，它与生命化学中的偏向性有关，偏向于L氨基酸和D单糖而不是其他对映体形式。虽然通常被认为是一种几何性质，但手性也可以在“静态”的非手性分子中通过极端的旋转激发而动态地产生[参见a . Owens, a . Yachmenev, and J. kpper, arXiv:1802.07803]。chem-ph),(2018)]。旋转诱导手性的现象与一些多原子分子（如H2S或PH3）在高旋转激发下表现出的旋转能聚类效应密切相关。在这个项目中，我们将进行联合实验和理论研究，首次证明旋转诱导手性的影响：光学离心机旋转激发H2S （CH3D, CH4）分子形成手性簇态，这些手性簇态对应于几乎与单个S-H （C-H）键一致的轴顺时针（r -对映体）或逆时针（s -对映体）旋转。在离心脉冲期间施加强直流电场有利于一种旋转对映体形式，从而产生具有永久定向旋转角动量的动态手性分子。在这个项目的过程中，我们将全面研究由极端旋转激发引起的动态手性的各个方面，从创建和成像到控制其性质。这一新颖而未经探索的研究课题有望为分子体系中旋转诱导手性现象提供新的见解。鉴于手性对我们理解分子和材料行为的重要性，在非手性体系中创造手性的能力具有很大的实际意义。在基本层面上，对分子手性的理论认识的提高将有助于我们对物理、化学和生物过程的基本知识的了解。

Chirality is ubiquitous throughout nature and is conventionally associated with a chemical or optical activity of a molecule in either of its two enantiomeric (mirror-image) forms. Since its discovery by Louis Pasteur in 1848, there remain many open questions about the origin of chirality. Notably, the origin of biomolecular (homo)chirality, which is concerned with the bias in the chemistry of life that favours L amino acids and D monosaccharides over the other enantiomeric form, is a controversial and often debated subject.Although usually regarded as a geometric property, chirality can also be dynamically created in “statically” non-chiral molecules through extreme rotational excitation [see A. Owens, A. Yachmenev, and J. Küpper, arXiv:1802.07803 [physics.chem-ph], (2018)].The phenomenon of rotationally induced chirality is closely connected to the effect of rotational energy clustering exhibiting by some polyatomic molecules, such as H2S or PH3, at high rotational excitation.In this project we will perform a joint experimental and theoretical investigation to demonstrate for the first time the effect of rotationally-induced chirality: An optical centrifuge rotationally excites the H2S (CH3D, CH4) molecule into chiral cluster states that correspond to clockwise (R-enantiomer) or anticlockwise (S-enantiomer) rotation about axes almost coinciding with single S—H (C—H) bonds. Application of a strong dc electric field during the centrifuge pulse favours one rotating enantiomeric form over the other, creating dynamically chiral molecules with permanently oriented rotational angular momentum. In the course of this project, we will comprehensively investigate all aspects of dynamic chirality induced by extreme rotational excitations, from creating and imaging through to controlling of its properties.This novel and unexplored research topic promises to offer fresh insights into the phenomenon of rotationally induced chirality in molecular systems. Given the importance of chirality to our understanding of molecular and material behaviour, the ability to create chirality in achiral systems is of great practical interest. On a fundamental level, an improved theoretical understanding of molecular chirality will contribute to our basic knowledge of physical, chemical, and biological processes.