Influence of Singlet-Triplet Mixing on the Hyperfine Structure of5sndRydberg States inSr87

Abstract
A systematic study of the hyperfine structure of 5snd D21 and D23 states of Sr87 was carried out by Doppler-free two-photon excitation. In the region of strong singlet-triplet mixing around n=16, the hyperfine structure exhibits a marked n dependence which is related to the amount of singlet-triplet mixing.