Multiple bonds at the experimental border:Spectroscopic characterization of high bond orders in molecular d- and f-element components

化学键是化学的核心。然而，对于最高键阶六重键的代表来说，实验研究的极限还没有耗尽。因此，到目前为止，锕系元素之间的化学键还没有经过任何实验表征。这一差距应该通过测量锕系元素分子来弥补，这些分子只被很少地研究过，甚至根本没有被研究过，以努力扩大实验知识的极限。这一目标可以通过研究气相过渡金属二聚体来实现，包括铀作为锕系元素的代表。事实上，它的气相二聚体从未被精确测量过。这种精密测量的选择方法是在绝热冷却分子射流的高分辨率傅里叶变换微波光谱与激光汽化技术相结合。不同同位素的高灵敏度测量，同时解码光谱精细和超精细结构，使得电子基态的Born-Oppenheimer近似之外的高度精确的解释，考虑到其几何和电子结构，这被预测为前所未有的复杂性。此外，激光汽化技术在配位化合物上的应用将使它们的结构——首次走这条路线——以一种新的方式可获得。

Chemical bonds are at the heart of chemistry. Nevertheless, the limits of experimental investigations are not nearly exhausted for representatives of the highest bond order, the sextuple bond. Consequently, the bonds between actinides have not been subject to almost any experimental characterization to date. This gap should be closed by measuring actinide molecules, that have only been investigated sparsely or even not at all, in an effort to significantly expand the limits of the experimental knowledge. This goal can be achieved by studying transition metal dimers in the gas phase, including uranium as a representative of the actinides. Its gas phase dimer in fact has never been subjected to a precise measurement. The method of choice for such precision measurements is high-resolution Fourier-transform microwave spectroscopy at adiabatically cooled molecular jets in combination with LASER vaporization technology. The highly sensitive measurement of different isotopologs with simultaneous decoding of spectral fine and hyperfine structure allows a highly precise elucidation beyond the Born-Oppenheimer approximation of the electronic ground state in view of its geometrical and electronic structure, which is predicted to be of unprecedented complexity. Furthermore, the application of the LASER vaporization technique to coordination compounds should make their structure - going this route for the first time - accessible in a new way.