Collisional perturbation of states in atomic ytterbium by helium and neon

Results of an investigation of collisional deexcitation of the metastable 6s6p³P₀ state in atomic ytterbium by helium and neon buffer gases are reported. We find upper limits for the quenching cross sections to be σHe<13×10^-22cm² and σNe<8×10^-22cm². The small cross sections may allow an ytterbium parity nonconservation experiment to be performed in a vapor cell. We have also measured the pressure broadening and shift of the 6s6p³P₀→6s7s³S₁ and 6s²¹S₀→6s6p³P₁ transitions by helium and neon.