Calculation of Coulomb interaction strengths for 3d transition metals and actinides

Coulomb interaction strengths (U/sub d//sub d/ and U/sub f//sub f/) have been calculated from Hartree-Fock-Slater atomic calculations for 3d transition and 5f actinide elements, respectively. By decomposing the different contributions to the response (screening) to the 3d charge fluctuation, we show that a substantial reduction in U/sub d//sub d/ arises due to the relaxation of the 3d charge distribution itself. This, combined with the screening due to the response of the 4s charge density, is shown to provide a very compact screening charge comparable to the metallic case, explaining the success of the atomic calculations for estimating U even in the metals. A pronounced dependence of U/sub d//sub d/ (or U/sub f//sub f/) on the number of electrons n/sub d/ (n/sub f/) or the electronic configuration is also shown here