Identification of the 3d 9 –3d 8 4f transition in Zr XIV

The XUV spectrum of Co i-like Zr was observed with a low-inductance vacuum spark by using a 10.7-m grazing-incidence spectrograph. Thirty-eight lines of the 3d9–3d84f transition and thirty levels of the 3d84f configuration in Zr xiv were identified for the first time, to our knowledge. The identifications were made with the aid of theoretical calculations based on the Slater–Condon theory of atomic structure. Observed and theoretical spectra and energy levels are displayed in the figures. In addition, energy levels and wavelengths with calculated weighted oscillator strengths are presented in the tables.