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，对于最高键级--六重键--的代表来说，实验研究的极限并不是几乎用尽。因此，到目前为止，几乎任何实验表征都没有涉及放线系元素之间的键。为了显著扩大实验知识的范围，这一差距应该通过测量仅被稀少研究甚至根本没有被研究过的鳗系元素分子来弥合。这一目标可以通过研究气相中的过渡金属二聚体来实现，包括以铀为代表的氡系元素。事实上，它的气相二聚体从未受到过精确的测量。选择这种精确测量的方法是在绝热冷却的分子射流中结合激光蒸发技术的高分辨率傅里叶变换微波光谱分析。对不同的同位素进行高灵敏的测量，同时解码光谱精细和超精细结构，允许高精度地解释电子基态的Born-Oppenheimer近似，因为它的几何和电子结构预计将具有前所未有的复杂性。此外，将激光蒸发技术应用于配位化合物，应该会使它们的结构--首次沿着这条路线--以一种新的方式获得。

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.