Molecular beam electron spin resonance to study the magnetic behaviour of super-atomic metal clusters

本项目的中心思想是建立一个Rabi实验，测量分子束中孤立团簇的电子自旋共振，以确定尚未达到精度的金属团簇的磁矩。典型的孤立群集实验技术显示系统和统计误差很少小于1%。相比之下，拉比频率允许以ppm范围内的实验精度确定磁矩，即比普通方法好两个数量级以上。迄今为止，还没有对较重的金属原子团簇进行过Rabi实验，因为自旋和旋转自由度的耦合通常会阻止在特定自旋状态下制备团簇。具有类原子磁性的内源性掺杂金属团簇的发现改变了这些前提条件，并且原则上可以进行此类团簇的Rabi实验。高精度磁矩是一种非常敏感的电子结构探针，即主簇笼与顺磁性客体原子之间的化学键。此外，这些实验允许研究没有干扰溶剂或基质效应的超精细相互作用。

The central idea of this project is to set up a Rabi experiment for measuring the electron spin resonance of isolated clusters in molecular beams in order to determine the magnetic moments of metal clusters with not yet reached accuracy. Typical experimental techniques for isolated clusters show systematic and statistical errors rarely less than 1 %. In contrast, the Rabi frequencies allow the determination of magnetic moments with an experimental accuracy in the ppm range, i.e. more than two orders of magnitudes better than common methods.Rabi experiments on clusters of heavier metal atoms have not been performed hitherto, since couplings of spin and rotational degrees of freedom usually prevent the preparation of a cluster in a defined spin state. The discovery of endohedrally doped metal clusters exhibiting atom-like magnetic properties has changed these preconditions and Rabi experiments on these type of clusters become available in principle. High precision magnetic moments are a very sensitive probe for their electronic structure, i.e. the chemical bonding between the host cluster cage and the paramagnetic guest atom. Further, these experiments allow the investigation of hyperfine interactions free of interfering solvent or matrix effects.