Non-bonding molecular spinors and tests of fundamental physics with laser-cooled ions

根据定义，非键合分子轨道是一种轨道，其中电子的移除或添加不会改变化学键强度。同时，非键分子轨道/旋量（NBMS）上的电子对于大量物理应用至关重要，例如，在分子（包括多原子分子）的直接激光冷却方面的最新进展基本上与对非键结旋量在产生闭合冷却循环中的作用的理解有关，闭合冷却循环是分子能够重新散射数千个光子所需的。激光冷却的分子/离子可以用于许多其他的基本应用，例如寻找永久的电子电偶极矩和测量核希夫矩。然而，识别具有所需性质（例如激光冷却性和对核希夫矩的敏感性）的分子是具有挑战性的，特别是它需要对具有占据NBMS的电子的分子电子结构的特性的基本理解。尽管NBMS的重要性，他们一直没有在理论和实验研究的中心，直到最近几年。我们以前已经定义了某些类别的NBMS，并确定了随后的分子适合激光冷却拥有一种或另一种类型的NBMS。在这个项目中，我们计划进行一个系统的理论研究的特殊作用NBMS的带电分子的电子结构。一方面将特别注意NBMS的基本理论，另一方面将特别注意不同的应用，如激光冷却，寻找奇异的宇宙场（包括冷暗物质）和分子离子中QED效应的测试。激光冷却的分子阳离子可以随后用于其他离子的交感冷却。

By definition, a non-bonding molecular orbital is an orbital, for which removal or addition of an electron does not change the chemical bond strength. At the same time, electrons on non-bonding molecular orbitals/spinors (NBMS) are of crucial importance for a wealth of physical applications, e.g., recent progress in direct laser cooling of molecules, including polyatomic ones, is essentially connected with understanding of the role of non-bonding spinors in the creation of closed cooling cycles, required for a molecule to be able to re-scatter thousands of photons. Laser-cooled molecules/ions can then be used for numerous other fundamental applications, such as the search for a permanent electron electric dipole moment and the measurement of the nuclear Schiff moment. Identification of molecules with desired properties (e.g. laser-coolability and sensitivity to nuclear Schiff moment) is challenging though, particularly it requires fundamental understanding of the peculiarities of the molecular electronic structure with electrons occupying NBMS. Despite the importance of NBMS, they have not been in the center of theoretical and experimental studies until recent years. We have defined previously certain classes of NBMS and identified subsequently molecules amenable for laser cooling possessing one or another type of NBMS. In this project we plan to undertake a systematic theoretical study of the particular role of NBMS in electronic structure of charged molecules. Special attention will be given on the one hand to the fundamental theory of NBMS and on the other hand to diverse applications such as laser cooling, search for exotic cosmic fields (including cold dark matter) and tests of QED effects in molecular ions. Laser-cooled molecular cations can be used subsequently in sympathetic cooling of other ions.