Norm conserving pseudopotentials for iron with semicore states

Semicore states of transition metals such as iron are outside the reach of \u201cstan- dard\u201d pseudopotential of DFT which, even when non linear core corrections are adopted, include them in the frozen atomic core. In this work we present an analysis of several pseudopotentials for iron generated in the Troullier Mar- tins and Hamann scheme assuming both local density and generalized gradient approximations (LDA, GGA) for the exchange\u2013correlation functional and con- sidering core-valence partitions with and without including semicore orbitals among valence states. Non linear core corrections are considered and the pseu- dopotential transferability has been checked. We calculate structural and elec- tronic properties of the \u3b1 phase of iron and we present a comparison between calculated optical conductivity and experimental data