~7LiH分子的基态X^1Σ^+和激发态A^1Σ^+、B^1Π与b^3Π的平衡几何与垂直激发能

Ab initio Calculation on Accurate Equilibrium Geometry and Vertical Excitation Energy for the Ground and Excited States X^1Σ^+, A^1Σ^+, B^1Π and b^3Π of ~7LiH molecule

使用分子反应静力学的有关原理,推导出了7L iH分子的基态X1Σ+、单重态的第一激发态A1Σ+、第二激发态B1Π以及三重态的第二激发态b3Π的合理离解极限.利用“对称性匹配蔟-组态相互作用”方法,在完全活性空间中计算了这一分子相应于上述各态的平衡核间距.其中,X1Σ+态为0.160 9 nm;A1Σ+和B1Π态分别为0.248 7和0.243 4 nm;b3Π态为0.195 8 nm.在基态的平衡位置处,计算了从基态到A1Σ+、B1Π及b3Π态的垂直激发能,其值分别为3.613、4.612和4.233 eV.将本文获得的计算结果与其它理论方法获得的计算结果及实验结果进行了比较,计算结果与实验结果吻合得很好;同时,本文获得的平衡核间距和垂直激发能与使用很复杂的方法获得的计算结果也相当接近.

The ceasonable dissociation limits of the ground and excited states （X^1∑^＋ ,A^1∑^＋ ,B^1∏ and b^3∏） of ^7LiH molecule are attained by employing the molecular reaction static theory. The accurate equilibrium geometries of the X^1∑^＋ ,A^1 ∑,B^1∏ and b^3 ∏ states of this molecule are firstly calculated by using a symmetry-adapted-cluster configuration-interaction （SAC-CI） method in full active space,and are of 0. 160 9 nm for the X^1∑ state, 0.248 7 nm for the A^1∑ state,0.243 4 nm for the B^1∏ state and 0. 195 8 nm for the b^3 ∏ state,respectively. The vertical excitation energies from the ground state to the A^1 ∑,B^1 ∏ and b^3 ∏ states are calculated,and are of 3.613 eV for the A^1 ∑^＋ state,4.612 eV for the B^1 ∏ state and 4.233 eV for the b^3 ∏ state at the ground-state equilibrium separation, respectively. Comparison of the theoretical calculations of equilibrium interatomic separations for these states with those obtained by previous theories clearly show that the present work is in excellent agreement with experiments. And the vertical excitation energies from the ground state to these excited states are much close to those attained by the very complicated method.