Pressure broadening and shift of the rubidium D1 transition and potassium D2 transitions by various gases with comparison to other alkali rates

- Measured unknown broadening and shifts rates for the alkali D1 and D2 transitions.
- Provided a comparison between the broadening cross-sections for all alkali.
- Improved the fidelity of the measurement of the broadening and shift rates.
- Revealed possible discrepancies on rates associated with the potassium transitions.

The pressure broadening and shift rates for the K D2 (4P3/22←4S1/22) transition with N2, CH4, C2H6, C3H8, n-C4H10, and the noble gases were obtained for pressures up to 80 Torr and at a temperature of 55 °C by means of laser absorption spectroscopy. Additionally, the broadening and shift rates for the Rb D1 (5P1/22←5S1/22) transition for He, CH4, C2H6, C3H8, and n-C4H10 were obtained using the same techniques and under similar conditions. The K D2 collisional broadening rate, γL, for He, Ne, Ar, Kr, Xe, N2, CH4, C2H6, C3H8, and n-C4H10 are 19.84, 8.88, 18.65, 19.17, 22.19, 18.98, 27.78, 27.60, 27.70, and 33.48 MHz/Torr, respectively. The uncertainty in the broadening rates is typically less than 2.1%. The corresponding pressure induced shift rates, δ, are 0.52, −2.06, −5.52, −5.42, −7.01, −5.66, −8.38, −8.04, −9.22, and −9.37 MHz/Torr with an uncertainty of less than 1.8%. The Rb D1 collisional broadening rates for He, CH4, C2H6, C3H8, and n-C4H10 are 20.80, 32.78, 30.49, 33.05, and 29.61 with uncertainties typically less than 2.2%. The collisional shift rates for the Rb D1 transition are 5.80, −6.96, −7.88, −8.61, and −9.43 with uncertainties on the order of 1.1%. A comparison with the other alkali broadening and shift cross-sections is presented.