Extended analyses of Se VII and Se VIII

The spectrum of selenium was photographed in the 400–1200-Å wavelength region on a variety of spectrographs by using a triggered spark source. Seventeen of the eighteen levels of the 3d94d configuration of Se vii have been established. The revision of the J = 1 levels of the 3d95p and 3d9nf (n = 4–7) configurations has led to a revised value of the ionization limit of Se vii as 3d92D5/2 = 1 252 800 ± 100 cm−1 (155.3 eV). In Se viii all levels of the 3d84s configuration and missing levels of the 3d84p configuration have been determined. Several levels of the 3d84p configuration have also been revised. The parametric calculations support both analyses. Sixty-four additional lines have been classified in Se vii, and seventy-four additional lines have been classified in Se viii.