We review the solvation of atomic, molecular or cluster ions in HNDs. After briefly discussing the properties of snowballs in bulk helium we consider experimental conditions for the efficient synthesis of charged, doped HNDs. We show that the cluster ions observed in conventional mass spectrometers originate from fission of highly charged HNDs. The ionization threshold of HNDs doped with alkalis reveals the minimum cluster size required for full immersion. The abundance distributions of He X ions frequently reveal local anomalies or magic numbers. We demonstrate that the abundance is approximately proportional to the evaporation energy. Observed and calculated magic numbers will be compiled, including data for ions solvated in molecular hydrogen. Alternative methods to forming He X that do not employ HNDs will be summarized. Electronic excitation spectra of C and polycyclic aromatic hydrocarbon ions reveal the properties of the helium adsorption layer in quantitative detail. Next we discuss theoretical efforts to describe the interaction between ions and helium. We close with summarizing the size dependence of physical quantities computed for atomic alkali and alkaline earth cations in helium, such as binding energy, superfluid fraction, structural order, radial density profiles, and the existence of first and higher solvation shells.

中文翻译：

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氦中离子的溶剂化

我们回顾了 HND 中原子、分子或簇离子的溶剂化。在简要讨论了大量氦气中雪球的特性后，我们考虑了有效合成带电掺杂 HND 的实验条件。我们表明，在传统质谱仪中观察到的团簇离子源自高电荷 HND 的裂变。掺杂碱的 HND 的电离阈值揭示了完全浸入所需的最小簇大小。He X 离子的丰度分布经常揭示局部异常或幻数。我们证明丰度与蒸发能量大致成正比。将编译观察和计算出的幻数，包括溶解在分子氢中的离子的数据。将总结不使用 HND 形成 He X 的替代方法。C 和多环芳烃离子的电子激发光谱定量地揭示了氦吸附层的性质。接下来我们讨论描述离子和氦之间相互作用的理论工作。我们最后总结了为氦中原子碱金属和碱土金属阳离子计算的物理量的大小依赖性，例如结合能、超流体分数、结构顺序、径向密度分布以及第一和更高溶剂化壳的存在。