New even-parity fine structure levels of the Lanthanum atom discovered by means of optogalvanic spectroscopy

Abstract

Laser excitation of an Ar–La plasma, generated in a hollow cathode discharge lamp, has allowed to us observe a huge number of spectral lines that could not be interpreted as transitions between already known La energy levels. From the observed hyperfine structure patterns and fluorescence lines, we derived 37 new La levels, all with even parity, in the energy range between 38 000 cm−1 and 43 000 cm−1. The existence of these levels was then proved by excitations from other known lower levels.

The Puzzle of the La I Lines 6520.644 Å and 6519.869 Å

“…An accurate determination of the energy of the atomic levels is connected with accurate determination of transition wavelengths; for this we use a wave number calibrated Fourier-transform (FT) spectrum. First results based on this spectrum are already published, together with results of laser spectroscopic investigations [5]- [9]. Sometimes unclassified strong lines can be found in the FT emission spectrum.…”

“…This isotope has nuclear spin quantum number 7/2 [3], a magnetic dipole moment µ I = 2.7830455 (9) µ N and a small electric quadrupole moment Q = 0.20 (1) × 10 −28 m 2 [4]. Its energy levels show nice hyperfine splitting which can be used as finger print for the corresponding level.…”

Division B Commission 14 Working Group: Atomic Data

“…Al II (HFS): [26], Ar IX: [277], B II: [208], Br III: [140], Cl I: [300], Co II (forbidden): [256], Dy I: [292], Eu I (HFS,IS): [2,102,103,104], Fe VIII-IX: [230], Fe VIII-XVI: [37], Fe XI: [66], Fe XIII: [62], Fe XVI: [36], Fe XVII: [63], Fe XVIII: [54], Fe XVIII-XXV: [254], Gd I (IS,HFS): [145], I I: [124], K I: [51], K III: [22], La I: [106], Li I: [50], Mg VII-VIII: [177], Mn I (HFS): [25,165], Mn II : [46], N III: [112], Na I: [52], Nb I: [72,235], Nb I (HFS): [95], Nd II (HFS): [28], Ne IV : [170], Ni I: [288,291], O I: [204], O VI: [341], P II: [153], Pr I (HFS): [107,282,319], Pr II: [21], Pr II (HFS): [20], Ru I (IS,HFS): ...…”

New Energy Levels of Neutral Lanthanum Derived from an Optogalvanic Spectrum between 5610 and 6110 Å

“…The ground state has designation 5d6s 2 2 D 3/2 . Altogether, today, around 340 energy levels with even parity and 160 levels with odd parity are known [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”