Spectra of multiply charged oxygen ions were studied in the region between
1800 and 6000 Angstrom by the beam foil method. The beam energy was 2, 4, 6
and 9 MeV for the charge state identification. Most of the intense lines a
re classified as transitions between high n, l levels in O III to O VIII, w
here n ranges from 9 to 15. The lines due to transitions 5l-6l' in Li-like
O VI were investigated in detail in the 1800-2250 Angstrom region. Many lin
es around 2070 a were attributed to the transition of the type of 1s2s5l L-
4-ls2s6l' L-4' and 1s2p5l L-4-1s2p6l' L-4', where L = l and L' = l'.