The transition array 2p<sup>6</sup>3p3d–2p<sup>6</sup>3d<sup>2</sup> has been identified in the spectrum of magnesium-like Ar VII produced by electrical discharges in the vacuum-ultraviolet region. Twenty-five new transitions have been identified as combinations of levels of this transition array. From these transitions we have determined the levels of the 3d<sup>2</sup> configuration. It was also possible to determine the 2p<sup>6</sup>3p3d<sup>1</sup>D<sub>2</sub><sup>o</sup> level that was missed in the early research with the Ar VII spectrum. Hartree–Fock calculations with relativistic corrections were used to predict energy levels and transitions. Isoelectronic comparisons along the Mg I sequence are used to support the experimental results.
© 2001 Optical Society of America
A. G. Trigueiros, F. Callegari, N. Mansur, G. H. Cavalcanti, A. J. Mania, M. Gallardo, and J. G. Reyna Almandos, "3d2 Configuration in six-times-ionized argon, Ar VII," J. Opt. Soc. Am. B 18, 1718-1721 (2001)