激光冷却AlD分子的理论研究  

Theoretical Investigation on the Laser Cooling of AlD Molecule

作　　者：李胜周[1] 周莹 邢伟[1] LI Shengzhou;ZHOU Ying;XING Wei(College of Physics and Electronic Engineering,Xinyang Normal University,Xinyang 464000,China)

机构地区：[1]信阳师范学院物理电子工程学院,河南信阳464000

出　　处：《信阳师范学院学报（自然科学版）》2021年第1期22-29,共8页Journal of Xinyang Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(11274097);河南省高等学校重点科研项目(21A140023);河南省自然科学基金项目(212300410233)。

摘　　要：利用icMRCI+Q方法计算了AlD分子4个Λ-S态和8个Ω态的势能曲线.势能曲线已包含核价相关修正,相对论修正和将势能外推至完全基组极限.获得的光谱常数与先前理论值和实验值吻合.利用icMRCI方法计算了6个束缚Ω态间的跃迁偶极矩.计算结果表明:A^1Π1(υ′=0,1)→X 1Σ+0+(υ′′)跃迁有高度对角化分布的Franck-Condon因子和振动分支比,以及A^1Π1(υ′=0,1)有短的自发辐射寿命和窄的辐射宽度.以此用一束主冷却激光(λ00=420.96 nm)和两束再泵浦激光(λ10=443.00 nm和λ21=448.94 nm)构建了AlD分子的激光冷却方案.得到的A^1Π1(υ′=0)X^1Σ^+0+(υ′′=0)的多普勒温度和回弹温度分别为44.94μK和3.73μK.The potential energy curves for fourΛ-S and eightΩstates of the AlD molecule are calculated by using the valence internally contracted multireference configuration interaction approach with the Davidson modification(icMRCI+Q).The core-valence correlation and relativistic corrections are included.The extrapolation of potential energies to the complete basis set limit is made.Transition dipole moments(TDMs)between the six boundΩstates are also calculated by the icMRCI approach.The calculated spectroscopic constant s are in good agreement with the available experimental data and theoretical values.Based on the obtained potential energy curves and transition dipole moments,highly diagonal Franck-Condon factors and vibrational branching ratios are determined for the A^1Π1(υ′=0,1)→X^1Σ+0+(υ′′)transition,short spontaneous radiative lifetime and narrow radiative width for the excited state A^1Π1(υ′=0,1)are also predicted.On this account,the optical scheme of the laser cooling for AlD molecule is constructed with A^1Π1(υ′)X^1Σ+0+(υ′′)as the close-loop transition.The proposed laser drives X^1Σ+0+(υ′′)→A^1Π1(υ′)transition by using three wavelengths(main laser beamλ00=420.96 nm;two repumping laser beamsλ10=443.00 nm andλ21=448.94 nm).The Doppler temperature(T Doppler=44.94μK)and recoiltemperature(T Recoil=3.73μK)for the A^1Π1(υ′=0)X^1Σ+0+(υ′′=0)transition are also calculated.These results can provide theoretical support for the experimental study of laser-cooled AlD molecules.

关 键 词：光谱常数 自旋轨道耦合 Franck-Condon因子和辐射寿命 激光冷却 

分 类 号：O561.3[理学—原子与分子物理]