New odd-parity high-lying energy levels of the europium atom by resonance ionization spectroscopy

Abstract

Odd-parity energy levels of the neutral europium atom (Eu I) have been investigated by employing both single-colour and two-colour stepwise laser excitation using the technique of resonance ionization spectroscopy in a heat-pipe thermionic diode system. Fifty-two new odd-parity energy levels of Eu I have been found in the energy region 40 575 - 43 410 . The J values for most of these new energy levels have been assigned unambiguously. In addition to this, 19 odd levels which were reported earlier, in the region of our present study, have also been investigated; the assignments of J values to nine of these levels have been confirmed and four levels, which had no unique J assignments, have been assigned definite J values.

Experimental study of bound and autoionizing Rydberg states of the europium atom

“…Among the 38 transitions shown in Table 1, 14 have not been reported before, while the rest of them accord well with those reported in the literature in terms of energy. [17] Furthermore, the intensities of all observed spectral lines are also tabulated for the first time, providing some additional information about these states. For instance, the intensities of the newly discovered spectral lines are mostly weaker than those of transitions whose level energies have been reported before, which may partially explain why the previous work failed to observe them.…”

Resonance ionization scheme development for europium

“…reduced ion source temperatures, fast beam gating [10,11], low work function cavities [12] or the Laser Ion Source Trap (LIST) [13]. Presently several resonance laser ionization schemes for europium exist, making use of either three step schemes [14] or two step schemes [15]. In both cases dye laser were used, where the two step schemes have made use of UV pumped dye lasers, emitting light in the blue to green spectral range.…”

Study of even-parity highly excited states of Eu I with a three-colour stepwise resonant excitation

“…With the development of the tunable laser and high-resolution spectroscopy, the atomic highly excited states have been investigated extensively [1][2][3]. In particular, multi-step photoionization (MSPI) spectroscopy has been proved to be a more effective and suitable technique than conventional absorption spectroscopy [4][5][6] for studying the spectra of complex atoms [7][8][9].…”

“…Although there have also been some reports on the spectra of the highly excited states for the rare-earth atoms, they mainly focus on Gd and Yb atoms [14][15][16][17][18][19]. In recent years, some works on the states of the europium (Eu) atom have also been reported [2,9,[20][21][22][23][24], but most of them deal with odd-parity states. Therefore, this work will report the results of bound even-parity highly excited states of the Eu atom with the MSPI technique.…”