On the Stark broadening of Sr+ and Ba+ resonance lines in ultracold neutral plasmas

We report results of the Stark broadening calculations for Sr⁺ and Ba⁺ resonance lines in ultracold plasmas using semiempirical formulas and numerical computer simulation technique. The simulation results show that strong collisions dominate Stark broadening at very low electron temperatures and weak collision approximation used recently by Vrinceanu et al. cannot be applied in this temperature region. Consequently, the temperature trend of Stark widths and shifts changes from successfully used at elevated temperatures to an increasing trend with temperature, which is characteristic for strong collisions at low temperature.