Pressure dependence of Na resonance line broadening by Kr and Xe

The fluorescent spectrum of the Na D lines, pressure broadened by Xe and Kr, has been measured for noble-gas densities of 2×{}10¹⁹-3×{}10²⁰ cm^-3; at the lower density, the lines are isolated while, at the higher, they are severely blended. The spectra are obtained in normalized intensity units allowing the nonbinary behavior of the line wing intensity to be clearly observed. At the lower density the broadening is well characterized by isolated binary interactions; at the higher density multiple-perturber interactions dominate. Nonlinearities in the pressure dependence of shifts, widths, and satellite shape are reported.