Abstract
The influence of polarisation of the core by the valence electron on single-configuration relativistic Hartree-Fock oscillator strengths for the 6S 2S12/-6p 2P degrees 1/2,3/2 transitions in the Yb II, Lu II and Hf IV spectra has been studied. The core polarisation effect is included by introducing a polarisation potential in the one-electron Hamiltonian and by employing the corresponding correction for the transition dipole moment operator in the transition matrix element.