Line Identification of Atomic and Ionic Spectra of Holmium in the Near-UV. Part I. Spectrum of Ho I

The Fourier Transform spectra of a Holmium hollow cathode discharge lamp have been investigated in the UV spectral range from 25,000 up to 31,530 cm^-1 (317 to 400 nm). Two Ho spectra have been measured with neon and argon as buffer gases. Based on the intensity ratios from these two spectra, a distinction was made between atomic and ionic lines (ionic lines are discussed in an accompanying paper). Using the known Ho I energy levels, 71 lines could be classified as transitions of atomic Ho, 34 of which have not been published previously. Another 32 lines, which could not be classified, are listed in the literature and assigned as atomic Ho. An additional 370 spectral lines have been assigned to atomic Ho based on the signal-to-noise ratio in the two spectra measured under different discharge conditions, namely with buffer gases argon and neon, respectively. These 370 lines have not been previously listed in the literature.