Line Identification of Atomic and Ionic Spectra of Holmium in the Visible Spectral Range. I. Spectrum of Ho i

Spectra of a holmium hollow cathode discharge lamp with neon or argon as buffer gases have been measured with a Fourier Transform spectrometer. In the visible spectral range from 14,280 up to 25,000 cm(-1), or 400 to 700 nm, more than 4000 spectral lines were detected. Based on different signal-to-noise ratios in two spectra measured with different discharge conditions, we could distinguish between different elements and between different degrees of ionization of Ho. Altogether 2862 lines could be assigned to atomic Ho, 2417 of which had not been listed in literature up to now. Based on the known energy levels of atomic holmium, 987 lines have been classified, 627 of which have been classified for the first time.