利用双光子电离探测技术系统地研究了Eu原子的奇宇称态的光谱。双光子电离探测技术利用两步激发获得Eu原子奇宇称态的光谱：首先将第一步激光的波长固定, 而最后一步激光的波长在35 500~35 650 cm-1, 36 200~36 600 cm-1和46 650~46 950 cm-1三个能域范围扫描, 对处于奇宇称激发态的Eu原子进行双光子电离, 以实现探测其光谱信息的目的。本文系统地研究了35 500~35 650 cm-1, 36 200~36 600 cm-1和46 650~46 950 cm-1能域内的光谱特征, 报道了这些能域内具有特殊寿命的高激发态。通过对采用3种不同的激发路径获得的高激发态的光谱进行拟合, 不仅获得了这些高激发态能级位置、线宽和线型的信息, 而且还观察到奇宇称态光谱中的q反转现象。 此外, 通过分析所获得的3张奇宇称态的光谱, 首次证明了4f壳层的电子被激发的可能性, 该结果为检测新量子理论提供了可靠的实验依据。

The spectra of odd-parity states of Eu atom are studied systematically with two-photon ionization detection technique. The two-photon ionization detection technique is utilized to obtain the spectra of odd-parity states with the two-step excitation: the wavelength of the first step laser is fixed, while that of the last-step laser is scanned around the region of 35 500-35 650 cm-1, 36 200-36 600 cm-1 and 46 650-46 950 cm-1, respectively. The characteristics of spectra in the energy region of 35 500-35 650 cm-1, 36 200-36 600 cm-1 and 46 650-46 950 cm-1 are investigated, demonstrating the special lifetime of highly excited states within those energy regions. In this paper, three different excitation pathways are used, not only the energy levels, line width and line shape are obtained, but also the q-reversal phenomenon is observed in the odd-parity states spectra. Besides, by analyzing the odd-parity states spectra of Eu atom, it is demonstrated that the possibility of 4f electrons are excited for the first time.