Ab initio方法研究LaO分子的跃迁性质

Ab initio study on transition properties of LaO molecular

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A^2Πr→X^2Σ+以及A^2Πr→A′2Δr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A^2Πr态的自发辐射寿命和A^2Πr→X2Σ^+跃迁的弗兰克-康登因子,A^2Πr→X^2Σ^+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.

By employing aquantum 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-lyingΛ-S electronic states and transition diploe moment(TDM)of the A^2Πr→X^2Σ^+and the A^2Πr→A′2Δrtransition 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 A^2Πr→X^2Σ^+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 fiveΩstates are shown in the paper.These results will be beneficial for the related experimental.