激光冷却AlD分子的理论研究

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ic-MRCI方法计算了6个束缚Ω态间的跃迁偶极矩.计算结果表明:A1Π1(υ'=0,1)→X1Σ+0+(υ')跃迁有高度对角化分布的...

Theoretical Investigation on the Laser Cooling of AlD Molecule

The potential energy curves for four Λ-S and eight Ω states 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 bound Ω states are also calculated by the icMRCI approach.The calculated spectroscopic constants 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~1Π_1(υ′=0,1)→X~1Σ_(0+)~+(υ′′)transition,short spontaneous radiative lifetime and narrow radiative width for the excited state A~1Π_1(υ′=0,1)are also predicted.On this account,the optical scheme of the laser cooling for AlD molecule is constructed with A~1Π_1(υ′)?X~1Σ_(0+)~+(υ′′)as the close-loop transition.The proposed laser drives X~1Σ_(0+)~+(υ′′)→ A~1Π_1 (υ′)transition by using three wavelengths(main laser beam λ_(00)=420.96 nm;two repumping laser beams λ_(10)=443.00 nm and λ_(21)=448.94 nm).The Doppler temperature(T_(Doppler)=44.94μK)and recoiltemperature(T_(Recoil)=3.73μK)for the A~1Π_1(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.