Measurements of the Spectrum of Singly Ionized Argon between 320 and 520 nm

We report beam-foil measurements of the spectrum for Ar II. Totally 56 lines are measured. Most of them are mainly ascribed to 3d–4p, 4s–4p, 4p–4d and 4p–5s resonance transitions. These spectral lines are identified, among which 16 lines are new and accurately measured. Analyses of the spectra are based on a comparison with the other experimental results and calculated values.