Studies On Spectra Of The Bound And Autoionizing States Of The Sm Atom

The studies of bound and autoionizing states of the rare-earth atom play an important role in the subject of atomic physics, astrophysics and plasmas. In addition, investigation of the atomic bound and autoionizing states has recently received much attention, as it is related to many interesting fields, such as lasing without population inversion, laser isotope separation, development of new laser. The study of high-lying states of Sm atom is scanty, mainly due to the reason that the element has a half-filled 4f sub-shell, leading to very complex atomic spectra. The above complex features make the study on Sm atom very difficult and very meaningful. In this thesis, both spectra and properties of the high-lying states of the Sm atom are studied systematically.Firstly, the spectra of bound odd-parity states of the Sm atom are systematically studied with two-photon ionization detection method in the thesis. In addition, the spectra of bound even-parity states of the Sm atom are studied with photoionization detection method. For those bound odd-parity states, the transitions are not only confirmed by the present work with the information on their relative strengths, but also can be determined from one of the 4f66s2 7FJ (J=0-6) states to different odd-parity states with 4f66s6p and 4f55d6s2 electronic configurations. Furthermore, some of transitions are reported for the first time with their resonance wavelengths and relative strengths. On the other hand, based on the J-momentum selection rules of three excitation paths, a unique assignment of J-momentum for all observed bound even-parity states has been determined, eliminating all remaining ambiguities in the literatures. In addition, the information on their relative intensities is given.Secondly, the autoionizing Rydberg states of the Sm atom are investigated systematically by three-color resonant excitation scheme with two different excitation paths. The two intermediate states, 4f66s7s 7F0 and 4f66s7s 7F1, are employed for the paths I and II, respectively. 67 autoionizing Rydberg states are found with the paths I and II. Furthermore, the J-momentum can be assigned to most of them, and the relative intensities and widths of all transitions are given for the first time.Above all, the investigation of the atomic bound and autoionizing states of the Sm atom not only enriches the spectral information of the Sm atom, but also provides a lot of important information to many engineering fields.