State changing in collisions of Rb(ns) Rydberg atoms with HF

Rate constants for state changing in collisions of Rb(ns) Rydberg atoms (40{≤}n{≤}48) with HF molecules have been measured and have been calculated using a semiclassical approach. Agreement between the total rate constants measured experimentally and derived theoretically is very good. The results point to the near-resonant nature of n-changing collisions, but indicate that the rate constants for such reactions are less dependent on energy imbalance than suggested by calculations based on the impulse approximation.