The spectrum of singly ionized oxygen, O II

Abstract

The spectrum of singly ionized oxygen, O II, emitted by a spark-generated, electrodeless discharge light source, has been investigated in the wavelength range 2100-11 700 Å. About 740 lines, 359 of which have not been reported earlier, were measured. As a result the energies of about 50 new levels have been determined, and the O II term system now presented includes 254 levels. The quartet system is firmly connected to the doublet system by 56 identified intersystem lines. The ionization limits have been determined by applying the polarization formula to the 4f, 5f, 5g and 6g levels. The experimentally determined value for the lowest limit, 2s22p2 3P0, is 283 270.9 ± 0.5 cm−1 above the 2s22p3 4S3/2 ground state.