Ariyarathna Isuru R
Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
Phys Chem Chem Phys. 2021 Sep 14;23(34):18588-18594. doi: 10.1039/d1cp03146e. Epub 2021 Aug 17.
High-level electronic structure calculations were performed to analyze ground and excited states of neutral and cationic endohedral M@CH (M = K, Rb, Ca, Sr) and M@CH (M = Na, K, Rb). In their ground states, one or two electrons occupy a diffuse atomic s-type orbital, thus 1s and 1s superatomic electronic configurations are assigned for M = Na, K, Rb and M = Ca, Sr cases, respectively. These species populate 1p-, 1d-, 1f-superatomic orbitals in electronically excited states. The specific superatomic Aufbau model introduced for M@CH (M = K, Rb) is 1s, 1p, 1d, 2s, 1f, 2p, 2d, 1g, 2f. On the other hand, excited electronic spectra of M@CH (M = Ca, Sr) are rich in multireference characters. Excited states of bigger M@CH molecules were investigated up to the 1d level and the transitions were found to require slightly higher energies compared to M@CH. These superatoms possess lower ionization potentials, hence can also be categorized as superalkalis.
进行了高水平的电子结构计算，以分析中性和阳离子型内嵌M@CH（M = K、Rb、Ca、Sr）以及M@CH（M = Na、K、Rb）的基态和激发态。在它们的基态中，一个或两个电子占据一个弥散的原子s型轨道，因此对于M = Na、K、Rb的情况分别指定了1s超原子电子构型，对于M = Ca、Sr的情况分别指定了1s²超原子电子构型。这些物种在电子激发态中填充1p、1d、1f超原子轨道。为M@CH（M = K、Rb）引入的特定超原子构造模型是1s、1p、1d、2s、1f、2p、2d、1g、2f。另一方面，M@CH（M = Ca、Sr）的激发电子光谱具有丰富的多参考特征。对较大的M@CH分子的激发态进行了研究，直至1d能级，发现与M@CH相比，跃迁所需的能量略高。这些超原子具有较低的电离势，因此也可归类为超碱。
