AsO^+同位素离子X^2∑^+和A^2Π电子态的多参考组态相互作用方法研究

A multi-reference configuration interaction investigation of the X^2∑^+and A^2Π low-lying electronic states of AsO^+ isotope ion

采用包含Davidson修正多参考组态相互作用(MRCI)方法结合价态范围内的最大相关一致基As/aug-cc-pV5Z和O/aug-cc-pV6Z,计算了AsO^+(X^2Σ^+)和AsO^+(A^2Π)的势能曲线.利用AsO^+离子的势能曲线在同位素质量修正的基础上,拟合出了同位素离子^(75)As^(16)O^+和^(75)As^(18)O^+的两个电子态光谱常数.对于X^2Σ^+态的主要同位素离子^(75)As^(16)O^+,其光谱常数R_e,ω_e,ω_ex_e,B_e和a_e分别为0.15770 nm,1091.07 cm^(-1),5.02017 cm^(-1),0.514826 cm^(-1)和0.003123 cm^(-1);对于A^2Π态的主要同位素离子^(75)As^(16)O^+,其T_e,R_e,ω_e,ω_ex_e,B_e和a_e分别为5.248 eV,0.16982 nm,776.848 cm^(-1),6.71941 cm^(-1),0.443385 cm^(-1)和0.003948 cm^(-1).这些数据与已有的实验结果均符合很好.通过求解核运动的径向薛定谔方程,找到了J=0时AsO^+(X^2Σ^+)和AsO^+(A^2Π)的前20个振动态.对于每一振动态,还分别计算了它的振动能级、转动惯量及离心畸变常数,并进行了同位素质量修正,得到各同位素离子的分子常数.这些结果与已有的实验值非常一致.本文对于同位素离子^(75)As^(16)O^+(X^1Σ^+),^(75)As^(18)O^+(X^1Σ^+),^(75)As^(16)O^+(A^1Π)和^(75)As^(16)O^+(A^+Π)的光谱常数和分子常数属首次报导.

The potential energy curves（PECs） of AsO＋（X2∑＋） and AsO＋（A2Π） are investigated using the full valence complete active space self-consistent field（CASSCF） method through the highly accurate valence internally contracted multireference configuration interaction approach including Davidson correction（MRCI＋Q）.In the present calculations,the basis sets for As and O are aug-cc-pV5Z and aug-cc-pV6Z respectively.The spectroscopic parameters of the isotopes 75As16O＋ and 75As18O＋ are determined.The present values of Re,ωe,ωe,αe and Be for 75As16O＋（X2∑＋） are 0.15770 nm,1091.07 cm-1,5.02017 cm-1,0.514826 cm-1 and 0.003123 cm-1,respectively;the present values of Te,Re,ωe,ωe xe,αe and Be for75As16O＋（A2Π） are 5.248 eV,0.16982 nm, 776.848 cm-1,6.71941 cm-1,0.443385 cm-1 and 0.003948 cm-1,respectively,which are compared with those reported by previous investigations in the literature.And the comparison shows that excellent agreement exists between the present results and the experimentsal ones.With the PECs of AsO＋（X2∑＋） and AsO＋（A2Π） determined here,the first 20 vibrational states for each electronic state are determined when the rotational quantum number J equals zero（J = 0）.For each vibrational state,the vibrational level G（v）, inertial rotation constant Bv and centrifugal distortion constant Dv are evaluated when,J = 0,which are in good accord ance with the available experimental data.