Interpretation of a spectrum of laser irradiated strontium in the range 115-208 Å

Abstract

Multicharged ions of strontium have been produced by laser irradiation (0.53 μm) of strontium targets with laser intensities of about 1014 W/cm2 on the target. Their spectrum has been observed with a crystal spectrograph in the range 4.5-7 Å and with a grazing-incidence spectrograph from 115 to 208 Å. Eight prominent lines previously identified as Sr XXVII and Sr XXVIII were used as internal standards for deriving wavelengths of about ninety lines from 115 to 208 Å. Ab initio evaluations of energies and transition probabilities in Sr XXVII by the relativistic parametric potential method support the identification of the configurations 3s3p, 3p3d, 3s3d and 3p2 which are now almost complete. Some weaker lines are attributed to Al-like Sr XXVI and Ne-like Sr XXIX.

Electron-impact excitation of Xe26+and its resultant spectral signature

“…Interest in the x-ray lasing transition 3d 9 4d 1 S 0 → 3d 9 4p 1 P 1 in Ni-like ions means that an accurate separation for these two levels is known (see Li et al (1998)). As noted by Wyart (1987), the ab initio predicted position of the upper level is too high. We have lowered this upper level by 0.56 Ry so as to match the separation reported by Li et al (1998).…”

“…Skobelev et al (1999) also carried out extensive theoretical calculations, including MCDF, but only reported results for those levels which are dipole-connected to the ground. Wyart (1987) has carried out Slater-Condon-type calculations for the 3d 9 4s, 4p and 4d levels of Ru 16+ through Sn 22+ based on fitting the Z-expansion coefficients to observed energies for the 3d 9 4s and 4p levels in Mo 14+ . We have carried out similar structure calculations for Mo 14+ and Ag 19+ .…”

“…We have carried out similar structure calculations for Mo 14+ and Ag 19+ . Based upon the comparison of the resultant energy levels with those of Wyart (1987), we have lowered our ground-state energy of Xe 26+ by 0.1 Ry.…”

Oscillator strength anomalies in the neon isoelectronic sequence with applications to x-ray laser modelling

“…2p 3/2 4d 5/2 [J = 1]: present work --; Cornille et al (1994) •; Zhang et al (1989) . neon-like strontium spectrum have been identified by Wyart et al (1987), and Keane et al (1990) observed soft x-ray amplification in a laser-produced strontium plasma. The table reveals good agreement between the different theories for the strongest RTP (greater than 10 9 s −1 ), but continued disagreement for the 2p3p[0]-2p3s[1] group as discussed by Ivanov et al (1995).…”

“…IG: present work; Q: Quinet et al (1991); C: Cornille et al (1994). Experimental wavelengths: w: Wyart et al (1987), k: Keane et al (1990) created by a high-contrast, high-intensity, short-pulse laser driver. If the ionization and dielectronic recombination rates are nearly balanced, the duration of the lasing under these conditions is determined by plasma cooling rather than by the rate of disappearance of the Ne-like ionization stage.…”