Temperature dependence of the helium induced broadening and shift of the Rb D1 and D2 lines

The rates for collisional broadening and shifting of the Rb D-1 (5(2)S(1/2) - 5(2)P(1/2)) and D-2 (5(2)S(1/2) - 5(2)P(3/2)) transition induced by He-4 have been measured at elevated temperatures of 373-723 K. The shift coefficients exhibit an increase of 20% from 4.36 MHz/Torr to 5.35 MHz/Torr for the D-1 line and an 80% increase from 0.42 MHz/Torr to 0.99 MHz/Torr for the D-2 line over the observed temperature range. Broadening coefficients exhibit a 6% increase from 17.8 MHz/Torr to 18.9 MHz/Torr and 10% from 18.5 MHz/Tory to 20.5 MHz/Torr for the D-1 and D-2 lines, respectively. The experimental values agree well with prior reported values within the temperature overlap regions of T < 394 K. Comparison to prior predictions from the Anderson-Talman theory using spin orbit multi reference (SOCI) ab initio potentials are superior to quantum treatments involving Allard and Baranger coupling. Published by Elsevier Ltd.