激光冷却KCl~–阴离子的理论研究  

Theoretical study of laser cooling of potassium chloride anion

作　　者：万明杰 罗华锋[2] 袁娣[1] 李松 Wan Ming-Jie;Luo Hua-Feng;Yuan Di;Li Song(School of Physics and Electronic Engineering, Yibin University, Yibin 644007, China;College of Chemistry & Chemical Engineering, Yibin University, Yibin 644007, China;School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China)

机构地区：[1]宜宾学院物理与电子工程学院,宜宾644007 [2]宜宾学院化学与工程学院,宜宾644007 [3]长江大学物理与光电工程学院,荆州434023

出　　处：《物理学报》2019年第17期98-104,共7页Acta Physica Sinica

基　　金：国家自然科学基金理论物理专项(批准号:11647075);计算物理四川省高等学校重点实验室开放课题基金(批准号:JSWL2018KFZ03)资助的课题~~

摘　　要：本文采用多组态相互作用方法计算了KCl^-阴离子前两个离解极限K(^2Sg)+Cl^-(^1Sg)和K(^2Pu)+Cl^-(^1Sg)所对应的3个电子态(X^2∑^+,A^2Ⅱ和B^2Σ^+)的电子结构.在计算中考虑了Davidson修正,核-价电子关联效应及自旋轨道耦合效应.预测了KCl^-阴离子的光谱常数和跃迁性质.计算得到(2)1/2(v’)←→(1)1/2(v")和(1)3/2(v’)←→(1)1/2(v")跃迁具有高对角分布的弗兰克-康登因子,分别为0.8816和0.8808;并且(2)1/2和(1)3/2激发态的自发辐射寿命分别为45.7和45.5 ns.分别利用(2)1/2(v’)←→(1)1/2(v")和(1)3/2(v’)←→(1)1/2(v")跃迁构建了准闭合的能级系统,冷却KCl^-阴离子所需的主激光波长分别为1065.77和1064.24 nm.同时预测了激光冷却KCl^-阴离子能达到的多普勒温度和反冲温度.计算结果为进一步激光冷却KCl^-阴离子的实验提供了理论参数.The potential energy curves and transition dipole moments(TDMs) for three ∧-S states(X2∑+, A2Ⅱ, and B2∑+) of potassium chloride anion(KCl–) are investigated by using multi-reference configuration interaction(MRCI) method. The def2-AQZVPP-JKFI of K atom and AV5 Z-DK all-electron basis set of Cl atom are used in all calculations. The Davidson correction, core-valence(CV) correction, and spin-orbit coupling effect(SOC)are also considered. In the complete active self-consistent field(CASSCF) calculations, eight molecular orbitals are selected as active orbitals, which includ K 4s4p and Cl 3s3p shells;K 3p shell is closed orbital, and the remaining shells(K 1s2s3s and Cl 1s2s2p) are frozen orbitals. In the MRCI+Q calculations, K 3p shell is used for the CV correction. There are 15 electrons in the correlation energy calculations. Then, their spectroscopic parameters, Einstein coefficients, Franck-Condon factors, and radiative lifetimes are obtained by solving the radial Schr?dinger equation. The spectroscopic properties and transition properties for the Ω states are predicted. Highly diagonally distributed Franck-Condon factor f00 values for the(2)1/2←→(1)1/2 and(1)3/2←→(1)1/2 transition are 0.8816 and 0.8808, respectively. And the short radiative lifetimes for the(2)1/2 and(1)3/2 excited states are also obtained, i.e.τ[(2)1/2]= 45.7 ns and τ[(1)3/2]= 45.5 ns, which can ensure laser cooling of KCl– anion rapidly. The results indicate that the(2)1/2←→(1)1/2 and(1)3/2←→(1)1/2 quasicycling transitions are suitable to the building of laser cooling projects. For driving the(2)1/2?(1)1/2 transition, a main pump laser(λ00) and two repumping lasers(λ10 and λ21) are required. Their wavelengths are λ00 = 1065.77 nm,λ10 = 1090.13 nm and λ21 = 1087.76 nm. For driving the(1)3/2←→(1)1/2 transition, the wavelengths are λ00 = 1064.24 nm,λ10 = 1088.54 nm, and λ21 = 1086.17 nm. The cooling wavelengths of KClanion for two transitions are both deep in the infrared range. Finally, the Doppler te

关 键 词：自旋-轨道耦合效应 弗兰克-康登因子 自发辐射寿命 激光冷却 

分 类 号：TN249[电子电信—物理电子学] O56[理学—原子与分子物理]