Disorientation and disalignment cross sections of excited Rb-atoms colliding with noble gases

The disorientation and disalignment cross sections for the depolarization of Rb 5²P_1/2 and 5²P_3/2 states due to collisions with the inert gases He, Ne, Ar, Kr, Xe were measured at a temperature of 317 K. The experiments were done in a static magnetic field H₀ which served to decouple the nuclear spin. Unpolarized Rb-D₂-radiation was made incident on the Rb-vapour parallel to H₀ thus generating an alignment in the²P_3/2-state. The linear polarization of the fluorescent D₂-light emitted at right angles towards the incident light beam was measured as a function of the rare gas pressure (0... 3 Torr). Similarly, for the disorientation measurements the vapour was excited by circularly polarized D₂- or D₁-radiation parallel to H₀ and circularly polarized fluorescent light was observed at small angles towards the backward direction. From the decrease of the polarizations observed at rising pressure the cross sections were determined. The comparison with theoretical results gives satisfactory agreement.