Spin exchange rate constant for collisions of metastable helium atoms with rubidium atoms

The spin exchange rate constant Cse in the He(23S1)-Rb(52S1/2) system has been measured for the first time in experiments on the optical orientation of metastable helium atoms in the presence of rubidium atoms. In the temperature interval T = 293–348 K, this value is Cse = (1.8 ± 0.4) × 10−9 cm3 s−1. The chemiionization rate constant, which has been simultaneously measured in collisions of these particles, is Cci = (3.1 ± 0.6) × 10−9 cm3 s−1.