Villarreal Pablo, Rodríguez-Cantano Rocío, González-Lezana Tomás, Prosmiti Rita, Delgado-Barrio Gerardo, Gianturco Franco A
Instituto de Fı́sica Fundamental, IFF-CSIC , Serrano 123, 28006 Madrid, Spain.
Institute of Ion Physics, The University of Innsbruck , Technikerstrasse 25, 6020 Innsbruck, Austria.
J Phys Chem A. 2015 Nov 25;119(47):11574-82. doi: 10.1021/acs.jpca.5b08470. Epub 2015 Nov 13.
We present variational calculations on systems containing a few boson helium atoms attached to electronically excited atomic and molecular helium anions He*⁻ and He₂*⁻ and characterize their structures and energetics. Previously reported high-level ab initio results [Huber, S. E.; Mauracher, A. Mol. Phys. 2014, 112, 794] to describe the interactions between excited (metastable) anions and a neutral He atom have been employed. For the case of the atomic species He*⁻, the corresponding interaction with He suggests large anharmonicity effects due to the presence of a deep well of ∼17,500 cm⁻¹ at short distances, together with a more external shallow secondary well of ∼4 cm⁻¹, both supporting bound levels. Moreover, when a sum of pairwise interactions is assumed to describe the full PES corresponding to the presence of several neutral He atoms, geometrical constraints already predict the complete solvation of the anionic impurity by six helium atoms, giving rise to a bipyramidal structure. In turn, for the anisotropic weak interaction He-He₂*⁻, where the anionic dimer is considered as a rigid rotor, the obtained structures show the tendency of the helium atoms to pack themselves together and largely far away from the dopant, thereby confirming the heliophobic character of He₂*⁻.
我们对包含几个与电子激发的原子和分子氦阴离子He*⁻和He₂*⁻相连的玻色子氦原子的系统进行了变分计算，并对其结构和能量进行了表征。此前已报道了用于描述激发（亚稳态）阴离子与中性He原子之间相互作用的高水平从头算结果[Huber, S. E.; Mauracher, A. Mol. Phys. 2014, 112, 794]。对于原子物种He*⁻的情况，其与He的相应相互作用表明，由于在短距离处存在约17,500 cm⁻¹的深阱以及约4 cm⁻¹的更外部浅二级阱，二者都支持束缚能级，因此存在较大的非谐效应。此外，当假设成对相互作用的总和来描述与几个中性He原子存在相对应的完整势能面时，几何约束已经预测阴离子杂质会被六个氦原子完全溶剂化，从而产生双锥结构。反过来，对于各向异性的弱相互作用He-He₂*⁻，其中阴离子二聚体被视为刚性转子，所获得的结构表明氦原子有聚集在一起并远离掺杂剂的趋势，从而证实了He₂*⁻的憎氦特性。
