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

这个项目的中心思想是建立一个拉比实验来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。孤立星系团的典型实验技术显示，系统误差和统计误差很少低于1%。相比之下，Rabi频率可以在ppm范围内以实验精度测定磁矩，即比常用方法高出两个数量级以上。迄今为止，还没有对较重的金属原子团进行拉比实验，因为自旋和旋转自由度的耦合通常会阻止在定义的自旋态下制备团簇。具有类似原子性质的面内掺杂金属团簇的发现改变了这些前提条件，对这类团簇的Rabi实验原则上是可行的。高精度的磁矩是对其电子结构非常敏感的探针，即主体团簇笼子和顺磁性客体原子之间的化学键。此外，这些实验允许在没有干扰溶剂或基质影响的情况下研究超精细相互作用。

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.