Radiative lifetime measurement of 1 S 0 metastable state of Ar2+ using electrostatic ion beam trap

The radiative lifetime of the 3s²3p^{4 1}S₀ metastable state of Ar²⁺ was measured using an electrostatic ion beam trap. The lifetime was obtained by measuring the number of photons emitted during the ¹S₀ → ³P₁ magnetic dipole transition of Ar²⁺ as a function of the storage time. The wavelength of the photons was 311 nm. To correct for the collision-induced loss of Ar²⁺ ions in the trap, the storage lifetime of the Ar²⁺ beam was measured simultaneously by detecting Ar neutrals escaping from the trap. The obtained radiative lifetime was 157 ± 19 ms, which was comparable to previously reported theoretical and experimental values.