Jp. Woerdman et al., MULTIPERTURBER EFFECTS IN THE FARADAY SPECTRUM OF RB ATOMS IMMERSED IN A HIGH-DENSITY XE GAS, Physical review. A, 53(2), 1996, pp. 1183-1186
We have measured the D-1 and D-2 Faraday spectrum and absorption spect
rum of Rb atoms immersed in high-density Xe buffer gas in the range n(
Xe) = 0.8-4.5X10(20) cm(-3). We find that the shape of the Faraday spe
ctrum obeys the Becquerel relation over this whole density range; howe
ver the relative strength of the Faraday effect compared to absorption
changes rather abruptly near n(Xe) = 1X10(20) cm(-3). This is ascribe
d to the onset of a many-body nature (overlapping collisions) of the R
b:Xe line broadening; the number of perturbers within the Weisskopf sp
here is unity at n(?)(Xe) similar to 1X10(20) cm(-3).