Pressure broadening and collisional shift of the Rb D2 absorption line by CH4, C2H6, C3H8, n-C4H10, and He

The pressure broadening and shift rates of the rubidium D2 absorption line 52S1/2→52P3/2 (780.24 nm) with CH4, C2H6, C3H8, n-C4H10, and He were measured for pressures ≤80 Torr using high-resolution laser spectroscopy. The broadening rates γB for CH4, C2H6, C3H8, n-C4H10, and He are 28.0, 28.1, 30.5, 31.3, and 20.3 (MHz/Torr), respectively. The corresponding shift rates γS are −8.4, −8.8, −9.7, −10.0, and 0.39 (MHz/Torr), respectively. The measured rates of Rb for the hydrocarbon buffer gas series of this study are also compared to the theoretically calculated rates of a purely attractive van der Waals difference potential. Good agreement is found to exist between measured and theoretical rates.

Research Highlights► Pressure broadening of the rubidium (Rb) D2 absorption line by hydrocarbon gases. ► Absorption spectroscopy of Rb. ► Diode pumped alkali metal vapor lasers (DPALs).