镱原子超精细诱导5d6s^(3)D_(1,3)→6s^(2)^(1)S_(0)E2跃迁及超精细常数的精确计算  

Accurate calculation of hyperfine-induced 5d6s^(3)D_(1,3)→6s^(2)^(1)S_(0)E2 transitions and hyperfine constants of ytterbium atoms

作　　者：赵国栋 曹进 梁婷 冯敏 卢本全[1,2] 常宏 Zhao Guo-Dong;Cao Jin;Liang Ting;Feng Min;Lu Ben-Quan;Chang Hong(National Time Service Center,Chinese Academy of Sciences,Xi’an 710600,China;Key Laboratory of Time Reference and Applications,Xi’an 710600,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 101408,China;Hefei National Laboratory,Hefei 230026,China)

机构地区：[1]中国科学院国家授时中心,西安710600 [2]时间基准及应用重点实验室,西安710600 [3]中国科学院大学天文与空间科学学院,北京101408 [4]合肥国家实验室,合肥230026

出　　处：《物理学报》2024年第9期58-69,共12页Acta Physica Sinica

基　　金：中国科学院战略性先导科技专项(B类)(批准号:XDB35010202)资助的课题.

摘　　要：在镱原子中,利用5d6s^(3)D_(1)→6s^(2)^(1)S_(0)跃迁探索宇称破缺效应已经得到了深入的研究.但是5d6s^(3)D_(1)态与基态6s^(2)^(1)S_(0)之间的M1跃迁和超精细诱导E2跃迁很大程度上影响了宇称破缺信号的探测.因此,很有必要精确计算5d6s^(3)D_(1)态与基态6s^(2)^(1)S_(0)之间的M1跃迁和超精细诱导E2跃迁的跃迁概率.本文利用多组态Dirac-Hartree-Fock理论精确计算了5d6s^(3)D_(1)→6s^(2)^(1)S_(0) M1跃迁和超精细诱导5d6s^(3)D_(1),3→6s^(2)^(1)S_(0) E2跃迁的跃迁概率.计算时详细分析了电子关联效应对跃迁概率的影响.此外,还分析了不同微扰态和不同超精细相互作用对跃迁概率的影响.本文计算的^(3)D_(1,2,3)和^(1)D_(2)态的超精细常数与实验测量结果符合得很好,从而证明了本文所用计算模型的合理性.结合实验测量的超精细常数和本文理论计算所得的核外电子在原子核处的电场梯度,重新评估了^(173)Yb原子核电四极矩Q=2.89(5)b,评估结果与目前被推荐的结果符合得很好.The parity violation effects via the 5d6s^(3)D_(1)→6s^(2)^(1)S_(0) transition have been extensively investigated in ytterbium atoms.However,the M1 transition between the excitation state 5d6s^(3)D_(1) and the ground state 6s^(2)^(1)S_(0),as well as the hyperfine-induced E2 transition,significantly affects the detection of parity violation signal.Therefore,it is imperative to obtain the accurate transition probabilities for the M1 and hyperfine-induced E2 transitions between the excitation state 5d6s^(3)D_(1) and the ground state 6s^(2)^(1)S_(0).In this work,we use the multi-configuration Dirac-Hartree-Fock theory to precisely calculate the transition probabilities for the 5d6s^(3)D_(1)→6s^(2)^(1)S_(0) M1 and hyperfine-induced 5d6s^(3)D_(1),3→6s^(2)^(1)S_(0) E2 transitions.We extensively analyze the influences of electronic correlation effects on the transition probabilities according to our calculations.Furthermore,we analyze the influences of different perturbing states and various hyperfine interactions on the transition probabilities.The calculated hyperfine constants of the e ^(3)D_(1,2,3) and ^(1)D_(2) states accord well with experimental measurements,validating the rationality of our computational model.By combining experimentally measured hyperfine constants with the theoretically derived electric field gradient of the extra nuclear electrons at the nucleus,we reevaluate the nuclear quadrupole moment of the ^(173)Yb nucleus as Q=2.89(5)b,showing that our result is in excellent agreement with the presently recommended value.

关 键 词：超精细诱导跃迁 镱原子 超精细常数 多组态Dirac-Hartree-Fock方法 

分 类 号：O562[理学—原子与分子物理]