Velocity dependence of the cross section for the quenching of Ar(3P0,2) and Kr(3P0,2) by O2

Measurements of the velocity dependence of the absolute cross sections for the quenching of metastable Ar(3P0,2) and Kr(3P0,2) by molecular oxygen were performed using a velocity selected metastable beam and a collision chamber. The Ar(3P0,2)−O2 cross section was equal to 35 Å and was independent of velocity for average relative velocities ḡ = 500–1700 m/sec. The Kr(3P0,2)−O2 cross section decreased as ḡ−1/5 from 500–1200 m/sec with a value of 39.5 Å2 at 600 m/sec. Application of an inhomogeneous magnetic field to the metastable beam showed that the 3P0 cross sections were larger than the 3P2 cross sections by 30 ± 20% and 60 ± 30% for Ar* and Kr*, respectively.