~6Li^(32)S双原子分子的光谱和辐射跃迁理论研究  

Theoretical study of the spectra and radiative transition properties of ~6Li^(32)S

作　　者：刘华兵[1] 袁丽[1] 李秋梅[1] 谌晓洪[1,2] 杜泉[1] 金蓉[1] 陈雪连[1] 王玲[1] 

机构地区：[1]西华大学理学院,成都610039 [2]西华大学先进计算中心,成都610039

出　　处：《物理学报》2016年第3期92-97,共6页Acta Physica Sinica

基　　金：西华大学研究生创新基金(批准号:ycjj2014132);西华大学研究生创新基金(批准号:ycjj2015165);四川省教育厅重点项目(批准号:14ZA0113)资助的课题~~

摘　　要：在aug-cc-pV5Z/CASSCF/MRCI水平上讨论了~6Li^(32)S双原子分子的9个较低能量电子态(X^2∏,a^4△,B^2△,b^4△,A^2∑^+,C^2∏,F^2∑^-,E^2∑^+和D^2∏)的势能函数和光谱常数;其中基态平衡核间距、谐振频率、转动常数等均与实验值相符;b^4∏,C^2∏,D^2∏态的平衡核间距均超过了0.4 nm,并且离解能较小,不稳定.D^2∏态是离子对态,离解极限为Li^+(~1S_g)+S^-(~1S_g).预测了最低激发态A^2∑^+跃迁到基态X^2∏的电子跃迁偶极矩、爱因斯坦自发发射系数、弗兰克-康登因子和辐射寿命.Low-lying electronic states（X2∏,A2∑＋,a4Δ,B2Δ,b4∏,C2∏,F2∑-,E2∑＋ and D2∏） of the 6Li（32）S molecule are computed at the aug-cc-pV5Z/MRCI level.The potential energy curves are presented for these states;the corresponding spectroscopic constants are reported.Electronic transition moment,Einstein coefficients,Frank-Condon factors and radiative lifetimes for the A2∑＋-X2∏,B2A-X2∏,C2∏-X2∏ systems are calculated.The balanced distance between two nuclei,harmonic frequencies and inertia moment of ground state X2∏ are predicted in this paper,and they are in accordance with their corresponding experimental data.The balance distances between the two nuclei in the electronic states of b4∏,C2∏,D2∏ are all longer than 4 A,so they are very unstable.The D2∏ electronic state will dissociate to Li十ion and S- ion：they are far from each other.The electronic transition dipole moment,Einstein coefficient,FranckCondon factor and radiative lifetime in transition from lowest excited A2∑＋ state to ground state X2∏ are predicted in this paper.The electronic transition dipole moments from three low lying electronic state A2∑＋,B2Δ and C2∏ to the ground state X2∏ are calculated at the aug-cc-pVSZ/MRCI level.The results show that the electronic transition dipole moment of A2∑＋→X2∏ has a small positive value while the nucleus distance is short,and rapidly decreases down to a small negative value with the nucleus distance increasing to around balance distance.Then it is stable about zero value while the nucleus distance continually increases.The electronic transition dipole moment of B2Δ→X2∏ has a small negative value（which is larger than that of A2∑＋→X2∏） at a short nucleus distance,and rapid increases up to a small positive value with the nucleus distance increasing to about balance distance.Then it slows down to zero while the nucleus distance increases to about 4 A.Finally it turns stable about zero value while the nuclei distance continually increases.

关 键 词：爱因斯坦系数 弗兰克-康登因子 辐射寿命 势能函数 

分 类 号：O561.3[理学—原子与分子物理]