Ground-state spectroscopy of multiply charged anions in the gas phase

多电荷阴离子（MCA）是凝聚相中常见的结构单元。几十年来，它们在固体和溶液中的存在已经得到了很好的证实。然而，由于它们在气相实验中的脆弱性，不受稳定抗衡离子和配体影响的孤立MCAs的性质和基本性质一直是未知的。一个专门的实验计划解决孤立的MCA的基态性质需要超高真空条件，以抑制这些很少产生的离子损失，高活性物种。此外，最低的黑体辐射是至关重要的，以防止它们被光剥离破坏。在我以前的工作和初步研究中，采用快离子束（CTF）和低温存储环（CSR）在海德堡的马克斯-普朗克研究所我已经证明了多功能性的静电存储设备在低温下的准无背景光谱实验。例如，利用激光诱导延迟电子脱离精确地监测内能的演化为复杂分子系统的动力学提供了新的见解。随着新型低温储存环装置的出现，实验研究主要受到弱束缚阴离子系统在其振转基态的产生不足的限制。因此，我建议在格赖夫斯瓦尔德大学开发一个低温3态数字离子阱，用于在最低振转态中创建MCA。这种设置将首先用于探索最小的，极弱结合的多电荷阴离子系统。特别是，我将寻找最小的双阴离子簇系统是稳定的电子损失。在第二步中，我建议将低温三态数字离子阱设置与海德堡的CSR相结合。在这里，离子阱将用于创建、积累和冷却处于最低量子态的MCA束，以注入CSR。我将研究寿命，离子-电子相互作用，离子-光子相互作用，以确定基本方面，如结合能和电子-电子相关效应的MCAs。一个关键实验是亚稳态双阴离子富勒烯C602-的寿命测量。总的来说，这些实验将揭示MCAs的基本性质及其在自然界中的作用。三态离子阱作为离子注入器的成功演示必将引发其在世界范围内许多实验中的应用。

Multiply charged anions (MCAs) are common building blocks in condensed phases. Their existence in solids as well as solutions is well established since many decades. Nevertheless, the nature and fundamental properties of isolated MCAs, unaffected by stabilizing counterions and ligands, have been unfathomed due to their fragility in gas-phase experiments. A dedicated experimental program addressing ground state properties of isolated MCAs requires ultra-high vacuum conditions to suppress ion loss of these rarely produced, highly reactive species. Furthermore, lowest blackbody radiation is crucial in order to prevent their destruction by photo-detachment. In my previous work and preliminary studies employing the Cryogenic Trap for Fast ion beams (CTF) and the Cryogenic Storage Ring (CSR) at the Max-Planck-Institut für Kernphysik in Heidelberg I have demonstrated the versatility of electrostatic storage devices at cryogenic temperatures for quasi background-free spectroscopy experiments. For example, the use of laser-induced delayed electron detachment for monitoring precisely the evolution of the internal energy offers new insights into the dynamics of complex molecular systems.With the advent of novel cryogenic storage ring setups experimental studies are mainly limited by an insufficient production of the weakly-bound anionic systems in their rovibrational ground states. Thus, I propose to develop a cryogenic 3-state digital ion trap at the University of Greifswald for creating MCAs in their lowest rovibrational states. This setup will first serve exploring the smallest, extremely weakly bound multiply charged anionic systems. In particular, I will search for the smallest dianionic cluster systems that are stable against electron loss. In a second step, I suggest combining the cryogenic 3-state digital ion trap setup with the CSR in Heidelberg. Here, the ion trap will be used to create, accumulate, and cool bunches of MCAs in their lowest quantum states for injection into CSR. I will study lifetimes, ion-electron interactions, and ion-photon interactions to determine basic aspects such as binding energies and electron-electron correlation effects of MCAs. A key experiment will be the lifetime measurement of the metastable dianionic fullerene C602-. In general these experiments will shed light on the basic properties of MCAs and their role in nature. A successful demonstration of the 3-state ion trap as ion injector will certainly trigger its application in many experiments worldwide.