Highly charged ions with E1, M1, and E2 transitions within laser range
Highly charged ions with E1, M1, and E2 transitions within laser range
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DOI：
10.1103/physreva.86.022517
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发表时间：
2012-06
影响因子：
2.9
通讯作者：
J. Berengut;V. Dzuba;V. Flambaum;A. Ong
中科院分区：
文献类型：
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作者：
J. Berengut;V. Dzuba;V. Flambaum;A. Ong
当核电荷Z和离子电荷Z_ion沿沿着等电子序列变化直到两个最外层几乎简并时，离子基态的能级交叉发生。我们研究了近中性离子和高电荷离子（HCIs）的周期表中所有可用的能级交叉。HCI中的正常E1跃迁在X射线范围内，然而能级交叉允许光学电磁跃迁，其可以形成高精度原子钟的参考跃迁。光学E1（由于配置混合），M1和E2跃迁在HCI中接近能级交叉处可用。我们提出了能量和振幅的标度定律，使我们能够对与原子钟相关的系统效应进行简单的估计。HCI时钟可能比现有的光学时钟具有一些优势，因为某些系统效应被减少，例如它们可以具有小得多的热偏移。其他效应，如精细结构和超精细分裂在HCI中要大得多，这可以允许更丰富的光谱。HCI是探测原子系统中精细结构常数α变化的绝佳候选者，因为存在对α变化具有最高灵敏度的跃迁。
Level crossings in the ground state of ions occur when the nuclear charge Z and ion charge Z_ion are varied along an isoelectronic sequence until the two outermost shells are nearly degenerate. We examine all available level crossings in the periodic table for both near neutral ions and highly charged ions (HCIs). Normal E1 transitions in HCIs are in X-ray range, however level crossings allow for optical electromagnetic transitions that could form the reference transition for high accuracy atomic clocks. Optical E1 (due to configuration mixing), M1 and E2 transitions are available in HCIs near level crossings. We present scaling laws for energies and amplitudes that allow us to make simple estimates of systematic effects of relevance to atomic clocks. HCI clocks could have some advantages over existing optical clocks because certain systematic effects are reduced, for example they can have much smaller thermal shifts. Other effects such as fine-structure and hyperfine splitting are much larger in HCIs, which can allow for richer spectra. HCIs are excellent candidates for probing variations in the fine-structure constant, alpha, in atomic systems as there are transitions with the highest sensitivity to alpha-variation.