Rare-Gas-Induced Broadening of Ca Principal Series Lines

Abstract

We have measured Ar- and Kr-induced broadening of the Ca 4 s 2 1 S -4 s n p \(^{1}P (6{\leqslant}n{\leqslant}10\)) and 4 s 2 1 S -3 d 4 p 1 P transitions by means of the total absorption method. In this regime of n , the broadening cross section increases to its maximum value with n and then decreases. The maximum value is 28×10 -14 cm 2 at n =8 for Ar and 72×10 -14 cm 2 at n =9 for Kr. Assuming that the interatomic potential is described as a superposition of the Fermi potential and the polarization potential, we have calculated the cross section on the basis of the classical broadening theory. This calculation agrees well with both the present result and that for the Na 3 S - n S transitions measured by Kachru et al . by means of the trilevel-echo technique.