The surprising metastability of TeH2+.
The surprising metastability of TeH2+.
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DOI：
10.1063/1.4809566
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
Antonio G. S. de Oliveira-Filho;F. R. Ornellas
中科院分区：
文献类型：
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作者：
Antonio G. S. de Oliveira-Filho;F. R. Ornellas
提出了对双原子二价 TeH(2+) 的多种电子态的高级从头算研究。构建了 Λ + S 和相对论 (Ω) 态的势能曲线，不仅表明了该系统的亚稳态，而且还表明了由于自旋轨道相互作用而产生的大能量分裂。这种效应在靠近 (2)π 和 (4)Σ(-) 态交叉的区域也非常显着，其中避免 Ω 态之间的交叉对能垒的高度有相对较大的影响。与 TeH 相比，只有两个束缚态（X1 (2)Π3∕2 和 X2 (2)Π1∕2）低于约 25,000 cm(-1)，在 TeH(2+) 的情况下，获得了更丰富的能量分布，表明电子跃迁的各种可能性。在这项研究结果的指导下，这些状态的实验表征现在对光谱学家来说是一个挑战。由于接近平衡区域，双正电荷以碲原子为中心，因此该系统中的结合可以合理化为分别在 Te(2+) 和 H 的 pz 和 s 轨道之间的简单共价键。随着核间距离的增加，Te(2+)的电子亲和力克服了H(+)的电子亲和力，系统解离成两个单电荷碎片。双电离谱的模拟补充了电子态的表征，质谱研究的结果证实了这种亚稳态物质的预测瞬态存在。
A high-level ab initio investigation of a manifold of electronic states of the diatomic dication TeH(2+) is presented. Potential energy curves for both Λ + S and relativistic (Ω) states are constructed not only making evident the metastability of this system, but also the large energy splitting due to spin-orbit interactions. This effect is also very significant in the region close to the crossing of the (2)Π and (4)Σ(-) states, where avoided crossings between the Ω states have a relatively large impact on the height of the energy barriers. In contrast to TeH, with only two bound states (X1 (2)Π3∕2 and X2 (2)Π1∕2) below about 25,000 cm(-1), in the case of TeH(2+) a much richer energy profile is obtained indicating various possibilities of electronic transitions. Guided by the results of this study, the experimental characterization of these states is now a challenge to spectroscopists. Since close to the equilibrium region the double positive charge is centered on the tellurium atom, the binding in this system can be rationalized as a simple covalent bond between the pz and s orbitals of Te(2+) and H, respectively. As the internuclear distance increases, the electron affinity of Te(2+) overcomes that of H(+) and the system dissociates into two singly charged fragments. A simulation of the double ionization spectra complements the characterization of the electronic states, and results of a mass spectrometric investigation corroborates the predicted transient existence of this metastable species.