A critical compilation and extended analysis of the NeIV spectrum

Since Moore published her well-known tables of atomic and ionic energy leve ls (in 1949-1951), the number of observed lines of the light atoms and thei r ions has grown significantly. The lack of complete and consistent up-to-d ate tables of spectral lines and energy levels, particularly of the neon-io ns spectral notably reduces possibilities of interpretation of astrophysica l and laboratory spectra. In the present paper, all optical spectral lines of Ne IV observed in 24 previous works have been systematised together with recent observations made by means of the beam-foil method at Liege Univers ity. As a result of our extended analysis of the whole set of available dat a, 35 new energy levels have been found and 90 newly classified spectral li nes have been listed for the Ne IV spectrum, only a few of them having been reported previously. A complete table of observed and classified spectral lines has been built, and the list of optimised energy levels has been deri ved from it in a consistent way. A new, improved, ionisation potential of N e IV has been deduced from the experimental data.