Additions to the Spectrum of Fe IX in the 110–200 Å Region

The spectrum of eight-times ionized iron, Fe IX , was studied in the 110–200 Å region. A low inductance vacuum
spark and a 3 m grazing incidence spectrograph were used for the excitation and recording of the spectrum.
Previous analyses of Fe IX have been greatly extended and partly revised. The number of known lines in the
3p^(5)3d–3p^(5)4f and 3p^(5)3d–3p^(4)3d^(2) transition arrays is extended to 25 and 81, respectively. Most of the identifications
of the Fe IX lines from the 3p^(5)3d–3p^(4)3d^(2) transition array in the solar spectrum have been confirmed and several
new identifications are suggested.