On the properties of charged and neutral, atomic and molecular helium species in helium nanodroplets: interpreting recent experiments
On the properties of charged and neutral, atomic and molecular helium species in helium nanodroplets: interpreting recent experiments
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关于氦纳米液滴中带电和中性、原子和分子氦物种的特性：解释最近的实验
DOI：
10.1080/00268976.2013.863403
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发表时间：
2014-03-19
影响因子：
1.7
通讯作者：
Mauracher, Andreas
中科院分区：
文献类型：
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作者：
Huber, Stefan E.;Mauracher, Andreas
基态He(He-Boolean and(=)(1s(2)(1)S))，He=+(Boolean and He(1s(2)S))，He-2(+)((Boolean And)(=)He-2(1 sigma(2)(G)1 sigma(2)(G)1 sigma(U)和激发(亚稳态)He*(he-Boolean and(=)(1s2s(3)S))的性质，He-2*((布尔与)(=)he(2()1 sigma(2)(G)1 sigma(U)2 sigma(G)(3)sigma(+)(U)，He*(-)(He-Boolean and(=)(1s2s2p(4)p))和He-2*(-)(He-Boolean and(=)2(1 sigma(2)(G)1 sigma(U)2 sigma(G)1pi(U)(4)pig))用耦合簇法计算，基集乘以扩散函数。这项工作的目的是捕捉描述上述溶解在液态氦中的氦物种的定性不同行为所需的基本物理学。通过研究它们与原子基态氦的相互作用，发现基态He、He+、He-2(+)和激发态(亚稳态)He*-很好地结合在一个氦液滴中。相比之下，激发态(亚稳态)He-*、He-2(*)和He-2(*-)被挤出，这是因为它们在氦液滴中所需的大体积所带来的高能量成本。特别地，分子物种He-2(*)和He-2(*-)由一个以He-2(+)形式的正核组成，它被扩散的电子云包围，分别占一个或两个电子。讨论了这些结果对最近对氦纳米液滴的实验研究的影响，特别是对带负电荷的物种He*-和He-2(*-)的影响。我们发现，后一种物种在氦液滴中经历了完全不同的动力学，尽管它们在其他方面(例如扩散电子云、大小)非常相似，与实验观察很好地一致。
Properties of ground state He(He-boolean AND(=)(1s(2) (1)s)), He=+(boolean AND He(1s (2)s)), He-2(+) ((boolean AND)(=) He-2(1 sigma(2)(g)1 sigma(2)(g)1 sigma(u) (2)Sigma(+)(u))) and excited (metastable) He*(He-boolean AND(=)(1s2s(3)S)), He-2*((boolean AND)(=)He(2()1 sigma(2)(g)1 sigma(u)2 sigma(g) (3)Sigma(+)(u))), He*(-)(He-boolean AND(=)(1s2s2p(4)p)) and He-2*(-)(He-boolean AND(=)2(1 sigma(2)(g)1 sigma(u)2 sigma(g)1 pi(u) (4)Pi g)) are calculated using the coupled-cluster method and basis sets multiply augmented with diffuse functions. The aim of this work is to capture the essential physics needed to describe the qualitatively different behaviour of the above mentioned helium species dissolved in liquid helium. By studying their interaction with atomic ground state helium it is found that ground state He, He+, He-2(+) and excited (metastable) He*- are well bound within a helium droplet. In comparison excited (metastable) He-*, He-2(*) and He-2(*-) are found to be squeezed out due to the high energetic cost associated with the large volume they require inside a helium droplet. In particular, the molecular species He-2(*) and He-2(*-) consist of a positive core in the form of a He-2(+) which is surrounded by a diffuse electronic cloud accounting for one or two electrons, respectively. The implications of these results for recent experimental studies on helium nanodroplets are discussed, particularly for the negatively charged species He*- and He-2(*-). We find that the latter species experience completely different dynamcis in a helium droplet although they are very similar in various other respects (e.g. diffuse electron clouds, size) in good agreement with experimental observations.