From a first-principles density-functional (DF) calculation of the charge distribution all crystal-field (CF) parameters for the 4f states at the Sm site in ${\mathrm{SmCo}}_5$ have been evaluated. The calculation is based on an optimized linear combination of atomic orbitals scheme for the conduction-electron magnetism and on an ‘‘open 4f core shell’’ treatment of the localized Sm 4f moments. Real-space integrations are used to evaluate both on-site and lattice contributions to the CF parameters. It is explicitly shown that there is no justification in neglecting either of these contributions. In comparison to available experimental values, DF calculations are found to yield the correct sign for all CF parameters, but to overestimate considerably the magnitude of the most essential second-order parameter, ${\mathit{A}}_2^0$.

• Received 5 June 1992

DOI:https://doi.org/10.1103/PhysRevB.46.13919