Lawrence Livermore National Laboratory, Livermore, California 94550-9234, USA.
University of Notre Dame, Notre Dame, Indiana 46556, USA.
Phys Rev Lett. 2014 Jun 13;112(23):233003. doi: 10.1103/PhysRevLett.112.233003.
High-resolution spectroscopy of the 2s(1/2)-2p(1/2) transition in the extreme ultraviolet region is shown to resolve the level splitting induced by the nuclear magnetic field of both the 2s(1/2) and the 2p(1/2) levels in lithiumlike (141)Pr(56+) and of the 2s(1/2)2p(1/2) (3)P(1) level in berylliumlike (141)Pr(55+). The (141)Pr ions are an ideal test of this measurement approach because their energy levels are known well from first principles and are unaffected by small energy contributions from QED and nuclear magnetization effects. The accuracy attained in the measured 196.5 ± 1.2 meV 2s(1/2) splitting is more than an order of magnitude better than that achieved before using crystal spectroscopy of the 2s(1/2)-2p(3/2) x-ray transition and at the level needed to implement a proposed scheme for disentangling the contributions from QED and nuclear magnetization effects in higher-Z ions, such as (209)Bi.
在极紫外区，对 2s(1/2)-2p(1/2)跃迁进行高分辨率光谱分析，结果表明，锂类(141)Pr(56+)中 2s(1/2)和 2p(1/2)能级的核磁场所诱导的能级分裂，以及铍类(141)Pr(55+)中 2s(1/2)2p(1/2)(3)P(1)能级的分裂均可分辨。(141)Pr 离子是这种测量方法的理想测试对象，因为它们的能级是根据第一性原理很好地确定的，不受 QED 和核磁化效应的小能量贡献的影响。在测量中获得的 196.5±1.2 meV 的 2s(1/2)分裂精度比以前使用 2s(1/2)-2p(3/2)x 射线跃迁的晶体光谱学所达到的精度提高了一个数量级以上，达到了实现更高 Z 离子（如(209)Bi）中 QED 和核磁化效应贡献分解方案所需要的精度。
