Study of hyperfine anomaly in 9,11Be isotopes

The hyperfine structure anomaly in Be+ ions is calculated with electronic wave functions, obtained as a solution of the Dirac equation with the Coulomb potential modified by the charge distribution of the clustered nucleus and two electrons in the 1s2 configuration. The nuclear wave function is obtained in the cluster model of Be isotopes. The sensitivity of the hyperfine structure anomaly to the clustering effects, in particulat, to the extended neutron distribution is studied.