On the effect of the hyperfine interactions on Recoil distance Doppler-shift lifetime measurements

The hyperfine interactions effect on the results from RDDS experiments is considered. Expressions for the influenced observables are derived within the context of application of the Differential decay curve method for data analysis. In particular, a formula for the lifetime is given where, on the one hand, measured quantities-peak areas of the shifted (fast) components and on the other hand, modeled perturbed angular distribution functions are taken into account. This formula allows for both study of the hyperfine interactions and correct derivation of the lifetime of the investigated level.