The electron-excitation, phase-shift method of Lawrence has been applied to the determination of radiative lifetimes of Ar II transitions. The measured levels, which are primarily those of 4p2S, 2P, 4D, were studied using transitions in the region from 1900–4500 Å. The Ar II lifetimes measured ranged from 1.2 to 10.6 nsec and involve a number of levels in which configuration interaction is present.
TERRY A. MATILSKY and JAMES E. HESSER, "Radiative Lifetimes of Ultraviolet Transitions of Argon II," J. Opt. Soc. Am. 59, 579-582 (1969)