Precision measurement of excited spectra of oxygen ions

Spectra of the ionized oxygen atom were researched with the Pro-500i monochromator equipped with CCD. The beam foil method was used at energy of 2 MeV in a 2 × 1.7 Tandem accelerator. In this work, we report 201 spectral lines determined in the region 250-350 nm, and most spectral lines were attributed to re, l energy level transitions from OII to OIV atoms. Our experimental results are in good agreement with existing theoretical calculations. Many lines reported in this paper have not been measured in past experiments, and a majority of them are week transitional lines.