Relevance of core-valence interaction for electronic structure calculations with exact exchange

The role of the core-valence interaction in electronic structure calculations with the exact exchange of density-functional theory is investigated by comparison of pseudopotential with all-electron results for diamond and lithium. The same full-potential framework is applied in the case of both approaches, checking carefully the convergence of all results. It is found that the all-electron band structures of both prototype solids are well reproduced by the pseudopotential scheme. While for lithium with its rather polarizable core minor deviations between pseudopotential and all-electron bands are observed, the differences are marginal for diamond. The corresponding band gaps differ by less than 0.1 eV. This result gives further credence to the use of pseudopotentials in combination with the exact exchange.