Temperature dependence of Cs-Cs+ charge-exchange cross sections

A charge-exchange optical-pumping experiment to study the temperature dependence of the Cs-Cs+ charge-exchange cross section sigma has been performed. Cs+ ions are polarised by resonant charge-exchange collisions with optically pumped Cs atoms. The Cs+ ion resonance linewidths are measured over the temperature range 20-26 degrees C. They are used to study the charge-exchange cross section as a function of temperature. The cross section sigma (Cs+ to Cs) varies inversely as the square root of the temperature. The charge-exchange cross section sigma (Cs+ to Cs) has also been re-measured and found to be (6.6+or-0.5)*10-14 cm2, in good agreement with theoretical calculations.