4d → 5p transitions in the EUV photoabsorption spectrum of La V, La VI and La VII

Abstract

The photoabsorption spectra of La V, La VI and La VII have been recorded in the 85–96 eV region using the dual laser plasma technique. 4d → 5p transitions from their ground configurations were observed and identified with the aid of Hartree–Fock with configuration interaction calculations. The excited states were found to decay by autoionization involving 5s or 5p electrons and rates for the different processes and resulting linewidths were calculated and compared with experiment.

Extreme ultraviolet photoabsorption spectra of the Ce VI–Ce X isonuclear sequence

“…In each of the spectra analysed here a mixture of ionization stages contributed. For plasmas produced under our experimental conditions, previous results [6][7][8][9][10][11][12][13] have shown that the relative ion populations can be estimated by employing the collisional radiative model of Colombant and Tonon [17]. The relative populations at different electron temperatures are shown in figure 2.…”

“…Spectra were recorded electronically using the dual laser plasma (DLP) technique, which involves the generation of both the absorbing species of interest and a synchronized bright backlighting source using two laser-produced plasmas [8]. The DLP technique is a versatile, unique and effective diagnostic tool for photoabsorption spectroscopy and has been successfully used for the study of low, intermediate and high ion stages [6][7][8][9][10][11][12][13]. In this experiment, a Nd:YAG 850 mJ 15 ns (full width at half-maximum, FWHM) Q-switched laser pulse tightly focused onto a tungsten rod generated a tungsten backlighting continuum emitting plasma formed at a power density approaching 1 × 10 12 W cm −2 .…”

“…In adjacent elements, inner-shell photoabsorption spectra of previous members of the iodine-like isoelectronic sequence Cs III [4], Ba IV [4][5][6] and La V [4,7] have been widely studied. Along the barium isonuclear sequence the photoabsorption spectra of Ba IV (iodine-like), Ba V (tellurium-like) and Ba VI (antinomy-like) have been explored by Murphy et al [6] in the 75-85 eV region using the dual laser plasma technique and discrete structure was observed due to 4d → 5p transitions from their ground configurations. The 4d → 5p photoabsorption spectra of La V (iodine-like), La VI (tellurium-like) and La VII (antinomy-like) were also investigated by Murphy et al [7] in the 85-96 eV region, using laser-produced plasmas.…”