Ab initio方法研究LaO分子的跃迁性质

doi:10.3969/j.issn.1000-1565.2020.02.003

摘要/Abstract

摘要： 采用量子化学计算方法,计算了LaO分子的电子结构和辐射跃迁性质.在多参考组态相互作用(MRCI)级别,计算了LaO分子的3个低Λ-S态势能曲线、永久偶极矩(PDM)和A²Π_r → X²Σ⁺以及A²Π_r → A^'2Δ_r跃迁的跃迁偶极矩(TDM).计算所获得的光谱常数与测得的实验值非常符合.基于获得的势能曲线和跃迁偶极矩,得到了A²Π_r态的自发辐射寿命和A²Π_r → X²Σ⁺跃迁的弗兰克-康登因子,A²Π_r → X²Σ⁺跃迁的弗兰克-康登因子展现出高对角性.另外,运用相同的基组和活性空间,考虑了3个低Λ-S态的自旋-轨道耦合效应,获得了5个Ω态的势能曲线和光谱常数.希望所获得的数据可以为以后实验观察LaO分子和激光冷却LaO分子提供有利的理论依据.

关键词: 激发态, 势能曲线, 自旋-轨道耦合, 弗兰克-康登因子

Abstract: By employing a quantum chemical calculation method,we computed the electronic structure and radiative properties of LaO molecule.The potential energy curves and permanent dipole moment(PDM)of three low-lying Λ-S electronic states and transition diploe moment(TDM)of the A²Π_r → X²Σ⁺ and the A²Π_r → A^'2Δ_r transition of the LaO molecule have been calculated at the multi-reference configuration interaction(MRCI)level of theory.The spectroscopic constants derive from our present work are in good agreement with previous theoretical and experimental values.We also achieved the Franck-Condon Factors(FCFs)and spontaneous radiative lifetimes for the A²Π_r → X²Σ⁺ transition based on the obtained potential energy curve and TDM.Moreover,we chose the same space orbits and basis set in subsequent calculations for the spin-orbit coupling at MRCI level.The PECs and the spectroscopic parameters together with previous theoretical value for the five Ω states are shown in the paper.These results will be beneficial for the related experimental.

Key words: excited states, potential energy curves, spin-orbit coupling, Franck-Condon factors

中图分类号:

O152

田颖,蒋刚. Ab initio方法研究LaO分子的跃迁性质[J]. 河北大学学报(自然科学版), 2020, 40(2): 125-131.

TIAN Ying,JIANG Gang. Ab initio study on transition properties of LaO molecular[J]. Journal of Hebei University (Natural Science Edition), 2020, 40(2): 125-131.

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