LDA+U CALCULATIONS FOR 4D-IMPURITIES IN RB

We present improved density functional calculations for the electronic structure of 4d transition metal impurities in Rb. Exchange and correlation are described by superimposing exchange and correlation corrections of the Anderson model in the mean field approximation on the paramagnetic potential of the local density approximation (LDA). In this way a more consistent description of the atomic limit is obtained. In all cases we find "ionic" d(n) configurations to be more stable than LDA configurations with equal occupations of all d-states. For a Rh-impurity two stable configurations are obtained, i.e. d8 and d9, differing in energy by only 0.1 eV.