Abstract
The impact broadening and shift of the sodium resonance lines by noble gases have been redetermined with improved instrumentation and data reduction allowing for asymmetries. An increase of width, shift and asymmetry with the heavy noble gases is noted, as is a D2 to D1 width ratio greater than one for helium and neon, but less than one for argon, krypton and xenon. Comparisons are drawn with different published calculations to show that the widths are accounted for by the Pascale-Vandeplanque potential whether with a fully quantal or a semiclassical impact broadening theory. On the other hand, the Nikitin-Roueff potential does not work well in this case. Available calculations of the shift are less satisfactory and no predictions of the observed asymmetries have been made.