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

多电荷阴离子(MCAS)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，分离的MCAS的性质和基本性质，不受稳定的反离子和配体的影响，由于它们在气相实验中的脆弱性，一直是未知的。一个解决孤立MCAS基态性质的专门实验计划需要超高真空条件来抑制这些很少产生的高活性物种的离子损失。此外，最低的黑体辐射对于防止它们被光分离破坏是至关重要的。在我之前的工作和使用海德堡Max-Planck-Institut für KernPhyk的快速离子束低温陷阱(CTF)和低温存储环(CSR)的初步研究中，我已经证明了在低温下用于准无背景光谱实验的静电存储设备的多功能性。例如，利用激光诱导的延迟电子剥离来精确地监测内能的演化，为复杂分子体系的动力学提供了新的见解。随着新型低温储存环的出现，实验研究主要受到弱结合阴离子体系在其振动基态中产生的不足的限制。因此，我建议在格雷夫斯瓦尔德大学开发一种低温三态数字离子陷阱，用于创建处于最低振荡态的MCAS。这个装置将首先用于探索最小的、极弱束缚的多电荷阴离子系统。特别是，我将寻找对电子损失稳定的最小的双阴离子团簇系统。在第二步中，我建议将低温三态数字离子陷阱装置与海德堡的CSR相结合。在这里，离子陷阱将被用来创建、积累和冷却处于最低量子态的MCAS束，以便注入CSR。我将研究MCAS的寿命、离子-电子相互作用和离子-光子相互作用，以确定MCAS的结合能和电子-电子关联效应等基本方面。一个关键的实验将是亚稳态双阴离子富勒烯C602-的寿命测量。总的来说，这些实验将阐明MCAS的基本性质及其在自然界中的作用。三态离子陷阱作为离子注入器的成功示范必将引发它在世界范围内的许多实验中的应用。

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.