搜索

x
中国物理学会期刊

基于冷分子离子HD+振转光谱的精密测量

Precision measurement based on rovibrational spectrum of cold molecular hydrogen ion

CSTR: 32037.14.aps.73.20241064
PDF
HTML
导出引用
  • 由一个质子、一个氘核和一个电子组成的氢分子离子“HD+”是最简单的异核双原子分子, 其有着丰富的、可精确计算和测量的振转跃迁谱线. 通过HD+振转光谱实验测量和理论计算的对比, 可实现物理常数的精确确定, 量子电动力学理论的检验, 并开启了超越标准模型新物理的探寻. 目前, HD+的振转跃迁频率确定的相对精度已经进入了10–12量级, 并由此获得了当前最高精度的质子电子质量比, 相对精度达到20 ppt (1 ppt = 10–12). 本文全面介绍了目前HD+振转光谱的研究现状与理论背景, 阐述了基于Be+离子协同冷却HD+分子离子的高精度振转光谱测量方法, 包括Be+离子和HD+分子离子的产生与囚禁, HD+外态冷却与内态制备, 双组分库仑晶体中HD+数目的确定, 以及HD+振转跃迁的探测. 最后, 文章展望了进一步提高频率测量精度的光谱前沿技术, 及同位素氢分子离子的振转光谱在未来研究中的发展前景.

     

    A molecular hydrogen ion HD+, composed of a proton, a deuteron, and an electron, has a rich set of rovibrational transitions that can be theoretically calculated and experimentally measured precisely. Currently, the relative accuracy of the rovibrational transition frequencies of the HD+ molecular ions has reached 10–12. By comparing experimental measurements with theoretical calculations of the HD+ rovibrational spectrum, the precise determination of the proton-electron mass ratio, the testing of quantum electrodynamics(QED) theory, and the exploration of new physics beyond the standard model can be achieved. The experiment on HD+ rovibrational spectrum has achieved the highest accuracy (20 ppt, 1 ppt = 10–12) in measuring proton-electron mass ratio. This ppaper comprehensively introduces the research status of HD+ rovibrational spectroscopy, and details the experimental method of the high-precision rovibrational spectroscopic measurement based on the sympathetic cooling of HD+ ions by laser-cooled Be+ ions. In Section 2, the technologies of generating and trapping both Be+ ions and HD+ ions are introduced. Three methods of generating ions, including electron impact, laser ablation and photoionization, are also compared. In Section 3, we show the successful control of the kinetic energy of HD+ molecular ions through the sympathetic cooling, and the importance of laser frequency stabilization for sympathetic cooling of HD+ molecular ions. In Section 4, two methods of preparing internal states of HD+ molecular ions, optical pumping and resonance enhanced threshold photoionization, are introduced. Both methods show the significant increase of population in the ground rovibrational state. In Section 5, we introduce two methods of determining the change in the number of HD+ molecular ions, i.e. secular excitation and molecular dynamic simulation. Both methods combined with resonance enhanced multiphoton dissociation can detect the rovibrational transitions of HD+ molecular ions. In Section 6, the experimental setup and process for the rovibrational spectrum of HD+ molecular ions are given and the up-to-date results are shown. Finally, this paper summarizes the techniques used in HD+ rovibrational spectroscopic measurements, and presents the prospects of potential spectroscopic technologies for further improving frequency measurement precision and developing the spectroscopic methods of different isotopic hydrogen molecular ions.

     

    目录

    /

    返回文章
    返回
    Baidu
    map