Schöpfer Gabriel, Bergmeister Stefan, Ončák Milan, Stromberg Ianessa, Mahmoodi-Darian Masoomeh, Scheier Paul, Echt Olof, Gruber Elisabeth
Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria.
School of Chemistry, University of Edinburgh, Edinburgh, UK.
Phys Chem Chem Phys. 2024 Apr 17;26(15):11482-11490. doi: 10.1039/d4cp00465e.
Many doubly charged heteronuclear dimers are metastable or even thermodynamically stable with respect to charge separation. Homonuclear dicationic dimers, however, are more difficult to form. He was the first noble gas dimer predicted to be metastable and, decades later, observed. Ne is the only other dicationic noble gas dimer that has been detected so far. Here, we present a novel approach to form fragile dicationic species, by post-ionization of singly charged ions that are embedded in helium nanodroplets (HNDs). Bare ions are then extracted by colliding the HNDs with helium gas. We detect homonuclear doubly charged dimers and trimers of krypton and xenon, but not argon. Our multi-reference calculations confirm the stability of Kr, Kr, Xe, Xe, and Ar, but put the stability of Ar towards dissociation to Ar + Ar into question.
许多双电荷异核二聚体相对于电荷分离是亚稳的，甚至是热力学稳定的。然而，同核双阳离子二聚体更难形成。He是第一个被预测为亚稳的稀有气体二聚体，几十年后被观测到。Ne是迄今为止唯一已被检测到的另一种双阳离子稀有气体二聚体。在这里，我们提出了一种形成脆弱双阳离子物种的新方法，即通过对嵌入氦纳米液滴（HNDs）中的单电荷离子进行后电离。然后通过使HNDs与氦气碰撞来提取裸离子。我们检测到了氪和氙的同核双电荷二聚体和三聚体，但未检测到氩的。我们的多参考计算证实了Kr₂、Xe₂和Ar₂的稳定性，但对Ar₂解离为Ar + Ar的稳定性提出了质疑。
