Singlet excited states of anions with higher main group elements
Singlet excited states of anions with higher main group elements
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较高主族元素阴离子的单线态激发态
DOI：
10.1080/00268976.2013.780105
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发表时间：
2013
影响因子：
1.7
通讯作者：
R. Fortenberry
中科院分区：
文献类型：
--
作者：
R. Fortenberry
以往的研究表明，某些小阴离子存在偶极束缚激发态。然而，已经报道了一些闭壳阴离子的价激发态，但到目前为止，那些具有单一价态激发态的阴离子中只有一个硅原子。为了研究含硅阴离子和其他高主族原子以及它们的第一排类似物的电子激发态性质，本工作采用高能级耦合团簇理论，将激发态能量重现到比实验更好的0.1 eV。在所研究的14个阴离子中，有9个阴离子具有不同的束缚激发态：CH2SN−，C3H−，CCSiH−，CCSH−，CCNH−2，CCPH−2，BH3PH−2，AlH3NH−2和AlH3PH−2。两个阴离子具有明确的价态：CCSiH−及其第一行类似物C3H−。在许多报道激发态的系统的第一激发态波函数的价态和偶极束缚特征中，似乎存在着实质性的混合，但这种混合在类AlH3NH−2和AlH3Ph−2阴离子中最为明显。在相应的自由基是强偶极的阴离子中包含第二行原子会增加任何类型激发态存在的可能性，但在迄今为止用这种方法考虑的体系中，只有小的闭壳层阴离子中的第14族原子的性质还被证明允许价单一激发态。
Previous studies have shown that dipole-bound excited states exist for certain small anions. However, valence excited states have been reported for some closed-shell anions, but those with singlet valence excited states have, thus far, contained a single silicon atom. This work uses high-level coupled cluster theory previously shown to reproduce excited state energies to better than 0.1 eV compared with experiment in order to examine the electronic excited state properties of anions containing silicon and other higher main group atoms as well as their first row analogues. Of the 14 anions involved in this study, 9 possess bound excited states of some kind: CH2SN−, C3H−, CCSiH−, CCSH−, CCNH−2, CCPH−2, BH3PH−2, AlH3NH−2 and AlH3PH−2. Two possess clear valence states: CCSiH− and its first row analogue C3H−. Substantial mixing appears to be present in the valence and dipole-bound characters for the first excited state wavefunctions of many of the systems reporting excited states, but the mixing is most pronounced with the ammonia borane-like AlH3NH−2, and AlH3PH−2 anions. Inclusion of second row atoms in anions whose corresponding radical is strongly dipolar increases the likelihood for the existence of excited states of any kind, but among the systems considered to date with this methodology, only the nature of group 14 atoms in small, closed-shell anions has yet been shown to allow valence singlet excited states.