Isotope Shift in Li and B2+

Abstract
The mass polarization or specific isotope shift of the 1s22s 2S and 1s22p 2P levels of Li and B2+ is calculated using open-shell type wave functions and the shifts of the resonance lines of 7Li relative to 6Li and of 11B2+ relative to 10B2+ are estimated to be 0.100 cm-1 and 0.688 cm-1 respectively compared with the observed values 0.157 cm-1, 0.930 cm-1J = 0) and 0.970 cm-1J = 1). The results are also compared with the values obtained using an alternative form of the mass polarization operator.