Measurement of the High-Order Nuclear Moments by Laser Cooling

利用二极管激光器建立了高分辨率原子束激光光谱装置。利用该实验装置，对稀土元素进行了高分辨率激光光谱分析和系统的研究。已经确定了许多原子级的超精细常数。推导了原子核处的电子密度，并与理论Hartree-Fock计算进行了比较。关于激光冷却，建立了一种利用多普勒效应测量原子束速度的方法。对Rb原子进行了激光冷却：由热原子束炉产生的速度约为400 m/s的Rb原子束被减速到70 m/s以下。进行了Li， K， Rb的激光- rf双共振光谱分析。激光-射频双共振光谱法具有精度高、实验装置简单等优点，可用于超精细结构的精确测量。通过这种精度测量，可以研究与核磁分布有关的超细异常和高阶超细相互作用。我们测量了杂散磁场下的射频共振谱。由于难以消除杂散磁场，该方法的精度高于传统方法的残余塞曼展宽。我们以小于1khz的精度测量了^<6,7>Li, ^<39,41>K和^<85,87>Rb的基态的超精细分裂。在此基础上推导了超精细构造常数和超精细异常。

High-resolution atomic-beam laser spectroscopic setup has been made using a diode laser. With this experimental setup, high-resolution laser spectroscopy has been performed and systematic studies have been carried out for the rare-earth elements. Hyperfine constants have been determined for many atomic levels. The electron density at the nucleus has been derive and compared with the theoretical Hartree-Fock calculation.Concerning the laser cooling, a method for measuring the atomic beam velocity has been established using the Doppler effect. Laser cooling has been performed for Rb atoms : the Rb atomic beam with the velocity of about 400 m/s, produced by the thermal atomic beam oven, has been decelerated to less than 70 m/s.Laser-RF double resonance spectroscopy of Li, K, and Rb has been carried out. The laser-RF double resonance spectroscopy has advantages of high precision and simple experimental setup, and is very useful to precisely measure the hyperfine structure. From such precision measurement, the hyperfine anomaly, related to the nuclear magnetic distribution, and the high-order hyperfine interaction can be investigated. We measured RF resonance spectra in the stray magnetic field. The precision of this method is higher than that of the conventional method in which residual Zeeman broadening is always involved owing to the difficulty of canceling stray magnetic field. We measured hyperfine splittings of the ground states for ^<6,7>Li, ^<39,41>K, and ^<85,87>Rb with the precision of less than 1 kHz. Then the hyperfine structure constants and the hyperfine anomaly have been derived.