Radiative lifetimes and collisional energy transfer rate constants in Ar of the Ar(3p55p) and Ar(3p55p′) states

The radiative lifetimes and collisional deactivation rate constants of Ar[3p5(2P01/2)5p] and Ar[3p5(2P03/2)5p] levels with argon atoms have been measured by time resolved laser induced fluorescence combined with a pulsed discharge for preparation of populations in the Ar(4s) precursor levels. The radiative lifetimes of Ar(5p) levels are 100–140 ns, and their two‐body deactivation rate constants are in the range of (1.2–5.6)×10−10 cm3 atom−1 s−1. About half of the two‐body energy transfer is intramultiplet relaxation. Only about 20% of the Ar(5p) radiative decay is via 5p–4s transitions; the reminder is via transitions to the 5s and 3d states. The radiative cascading through the 5s and 3d states populates the 4p states with conservation of the inner core configuration. From the time dependence of the emission intensities from the 4p levels, the radiative lifetimes of the 5s and 3d states were estimated to be ∼50 ns.