Prediction of a Nonvalence Temporary Anion Shape Resonance for a Model (H 2 O) 4 System
Prediction of a Nonvalence Temporary Anion Shape Resonance for a Model (H 2 O) 4 System
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模型 (H 2 O) 4 系统的非价临时阴离子形状共振的预测
DOI：
10.1021/acs.jpca.8b11881
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Falcetta, Michael F.
中科院分区：
文献类型：
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作者：
Kairalapova, Arailym;Jordan, Kenneth D.;Maienshein, Daniel N.;Fair, Mark C.;Falcetta, Michael F.
用从头计算方法证明了无净偶极矩的（H2O）4团簇模型体系存在非价暂时阴离子形状共振。团簇由两个水二聚体组成，它们之间的距离是变化的。每个二聚体具有弱结合的非价阴离子状态。对于大的分离的二聚体亚基，有两个绑定的非价阴离子状态（Ag和B2 usymmetry）对应的对称和不对称的组合的非价阴离子状态的两个二聚体亚基。随着二聚体亚基之间的分离减少，B2 u阴离子的能量增加，并成为暂时的阴离子形状共振。共振能量的真实的部分被确定为二聚体之间的距离的函数，并被发现单调增加从刚刚超过阈值到28毫电子伏的几何形状的范围内考虑。在相同的几何形状范围内，共振半宽度从0到21 meV变化。B2 u阴离子在结合和暂时时都具有非常扩散的电荷分布。有效的径向势的相互作用的多余的电子与集群有一个障碍，在大的距离所产生的电子-四极相互作用结合的排斥角动量（l= 1）的贡献。该势垒影响共振能量和其寿命。
Ab initio calculations are used to demonstrate the existence of a nonvalence temporary anion shape resonance for a model (H2O)4cluster system with no net dipole moment. The cluster is composed of two water dimers, the distance between which is varied. Each dimer possesses a weakly bound nonvalence anion state. For large separations of the dimer subunits, there are two bound nonvalence anion states (of Agand B2usymmetry) corresponding to the symmetric and asymmetric combinations of the nonvalence anion states of the two dimer subunits. As the separation between the dimer subunits is decreased, the B2uanion increases in energy and becomes a temporary anion shape resonance. The real part of the resonance energy is determined as a function of the distance between the dimers and is found to increase monotonically from just above threshold to 28 meV for the range of geometries considered. Over this same range of geometries, the resonance half-width varies from 0 to 21 meV. The B2uanion, both when bound and when temporary, has a very diffuse charge distribution. The effective radial potential for the interaction of the excess electron with the cluster has a barrier at large distance arising from the electron–quadrupole interaction in combination with the repulsive angular momentum (l= 1) contribution. This barrier impacts both the resonance energy and its lifetime.