Stark-broadening measurement and calculations for a singly ionized aluminum line

Using an electromagnetically driven shock tube and rapid scanning Fabry-Perot spectrometer, the Lorentzian half-width of the 4663-{} line of singly ionized aluminum was measured and found to be 0.45 {} ±{} 20% for an environment corresponding to Nₑ=10¹⁷ cm^-3 and Tₑ=18500 ^∘{}K. Semiclassical and semiempirical calculations yielded values of 0.56 {} and 0.41 {}, respectively, while the distorted-wave approximation gave 0.51 {}. Our measurement and the calculated values fall a factor of 5 below the results of a previous experiment.