Linewidths of four visible Xe II lines are measured in a conventional shock tube. The Stark effect is the dominant broadening mechanism. Electron densities vary widely over the range (1-15) × ${10}^{16}$ ${\mathrm{cm}}^{-3\mathrm{}}$, but temperatures remain in the narrow range 7800-8400 K. Great care has been taken to minimize possible systematic errors in the electron-density and optical-depth measurements.

• Received 2 December 1983

DOI:https://doi.org/10.1103/PhysRevA.29.3181