摘要
基于相关一致基组aug-cc-pV5Z,采用内收缩多参考组态相互作用方法计算了BD^+离子两个最低解离极限B^+(~1Sg)+D(~2Sg)和B+(~3Pu)+D(~2Sg)对应的5个Λ—S态(X^2Σ^+,A^2Π,B^2Σ+,a^4Π和b^4Σ^+)的势能曲线和跃迁偶极矩.根据计算结果,求解核运动的径向薛定谔方程得到相应电子态的振-转光谱常数、Franck-Condon(F-C)因子和振动能级辐射寿命.其中A^2Π—X^2Σ^+的F-C因子(f_(00)=0.923)、辐射寿命(τ=235 ns)满足激光直接冷却的条件.因此,我们基于分子转动跃迁提出了一个可实现Doppler激光冷却的光循环方案:A^2Π_(1/2)(υ′=0)—X^2Σ+(υ′′=0,1),其中υ′=0中包含2个转动能级,υ′′=0和υ′′=1中分别包含6个和4个转动能级.根据方案,模拟了激光冷却过程中的分子布居数动力学变化过程,并计算了初速度为100 m/s的BD^+,历经5.4 ms散射1150个光子可减速到4.6 m/s、温度为13 mK.
Based on consistent basis set aug-cc-p V5 Z, five low-lying potential energy curves and transition dipole moments X2Σ＋, A2Π, B2Σ＋, a4Π and b4Σ＋of BD＋ are calculated by using internally contracted multi-reference configuration interaction approach. According to the calculation results, ro-vibrational levels of theses electronic states are derived through solving the radial Schr？dinger equation ro-vibrational equation, and then the molecular parameters, FranckCondon factors（FCFs） and radiation life are obtained by fitting and calculations. The FCFs（f00= 0.923） and radiation life for υ′′= 0（τ = 235 ns） of A2Π–X2Σ＋are suitable for achieving rapid laser cooling. Therefore, an optical-cycle for Doppler laser cooling scheme is proposed： the system includes the A2Π1/2（υ′= 0）–X2Σ＋（υ′′= 0, 1）, where the case of υ′= 0 contains 2 rotational levels, the cases of υ′′= 0 and υ′′= 1 contain 6 and 4 rotational levels, respectively.According to the proposal, we simulate the dynamic process of the molecular population in laser cooling. The BD＋can be decelerated from initial velocity of 100 m/s to 4.6 m/s（13 m K） after scattering 1150 photons during 5.4 ms.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2017年第16期69-75,共7页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11504256
U1610117
61675120)
中国科学院时间频率基准重点实验室开放基金
精密光谱科学与技术国家重点实验室开放课题
山西省高等学校科技创新项目(批准号:2015166)
晋城市科技攻关项目(批准号:1201501004-22)
山西省高等学校创新人才支持计划
山西省回国留学人员科研资助项目(批准号:2016-096)资助的课题~~
