钐原子的两步激发共振光电离光谱

采用两步激发共振光电离技术研究了Sm原子的偶宇称高激发态光谱.实验采用了两条激发路线：1)第一束激光的波长固定在478.44nm以便将Sm原子从4f⁶6s²［⁷F₁］态激发至4f⁶6s6p［⁷D₁］态，再用第二束激光使其波长从480nm扫描至530nm，将Sm原子进一步激发至待测的高激发态；2)第一束激光的波长固定在574.8 关键词： Sm原子 光谱 分步激发 共振电离

Two-step resonant photoionization spectra of Sm atom

Resonant ionization spectra of Sm atom are studied with a two-step photoexcitation and photoionization method. Two different excitation paths are carried out as the following: In the path 1, the first laser whose wavelength is fixed at 478.44nm excites the Sm atom from the 4f⁶6s²［⁷F₁］ state to the 4f⁶6s6p［⁷D₁］ state，and then the second laser whose wavelength λ₂ is scanned from 480nm to 530nm excites it further to the high-lying state with even parity. In the path 2, the first laser whose wavelength is fixed at 574.81nm excites the Sm atom from the 4f⁶6s²［⁷F₂］ state to the 4f⁶6s6p［⁵G₃］ state，and then the second laser whose wavelength λ₂ is scanned from 460nm to 470.5nm excites it further to the high-lying state with even parity. These Sm atoms in the high-lying state are probed by photoionization via the third laser. All together 26 and 76 states of Sm atom in the 39465—39932 cm^-1 and the 40000—42010 cm^-1 energy region, respectively, have been detected below the first ionization limit. The energy levels and relative strengths of these states have been determined. Among them, 51 states are newly discovered, while the rest agree well with the values published in literature. In addition, efforts are also made to determine their spectral designation.