Skripnikov Leonid V, Schmidt Stefan, Ullmann Johannes, Geppert Christopher, Kraus Florian, Kresse Benjamin, Nörtershäuser Wilfried, Privalov Alexei F, Scheibe Benjamin, Shabaev Vladimir M, Vogel Michael, Volotka Andrey V
Department of Physics, St. Petersburg State University, Universitetskaya 7/9, 199034 St. Petersburg, Russia.
Petersburg Nuclear Physics Institute, B.P. Konstantinov of National Research Centre "Kurchatov Institute", 188300 Gatchina, Leningrad District, Russia.
Phys Rev Lett. 2018 Mar 2;120(9):093001. doi: 10.1103/PhysRevLett.120.093001.
A recent measurement of the hyperfine splitting in the ground state of Li-like ^{208}Bi^{80+} has established a "hyperfine puzzle"-the experimental result exhibits a 7σ deviation from the theoretical prediction [J. Ullmann et al., Nat. Commun. 8, 15484 (2017)NCAOBW2041-172310.1038/ncomms15484; J. P. Karr, Nat. Phys. 13, 533 (2017)NPAHAX1745-247310.1038/nphys4159]. We provide evidence that the discrepancy is caused by an inaccurate value of the tabulated nuclear magnetic moment (μ_{I}) of ^{209}Bi. We perform relativistic density functional theory and relativistic coupled cluster calculations of the shielding constant that should be used to extract the value of μ_{I}(^{209}Bi) and combine it with nuclear magnetic resonance measurements of Bi(NO_{3}){3} in nitric acid solutions and of the hexafluoridobismuthate(V) BiF{6}^{-} ion in acetonitrile. The result clearly reveals that μ_{I}(^{209}Bi) is much smaller than the tabulated value used previously. Applying the new magnetic moment shifts the theoretical prediction into agreement with experiment and resolves the hyperfine puzzle.
最近对类锂 (^{208}Bi^{80 +}) 基态超精细分裂的测量发现了一个“超精细难题”——实验结果与理论预测存在7σ的偏差[J. Ullmann等人，《自然通讯》8, 15484 (2017)NCAOBW2041 - 172310.1038/ncomms15484；J. P. Karr，《自然物理学》13, 533 (2017)NPAHAX1745 - 247310.1038/nphys4159]。我们提供的证据表明，这种差异是由 (^{209}Bi) 表格中列出的核磁矩 ((\mu_{I})) 值不准确所致。我们进行了相对论密度泛函理论和相对论耦合簇计算，以确定用于提取 (\mu_{I}(^{209}Bi)) 值的屏蔽常数，并将其与硝酸溶液中 (Bi(NO_{3}){3}) 以及乙腈中六氟铋酸盐(V) (BiF{6}^{-}) 离子的核磁共振测量结果相结合。结果清楚地表明，(\mu_{I}(^{209}Bi)) 比之前表格中使用的值小得多。应用新的磁矩使理论预测与实验结果相符，从而解决了超精细难题。
