Lifetime measurements of Rydberg states in the 6snd 1 D 2-series of BaI

We have measured the lifetimes of 10 Rydberg states from 6s8d ¹ D ₂ to 6s 17d ¹D₂ in the Ba I spectrum by time-resolved recording of the exponential decay of the resonance fluorescence in an atomic beam. The excitation was performed by use of two pulsed dye lasers simultaneously pumped by one nitrogen laser. The lifetime results differ strongly from Coulomb approximation calculations and show deviations from a(n ^*)³-dependence.