Validation of density functionals for transition metals and intermetallics using data from quantitative electron diffraction.

摘要: Accurate low-order structure factors (Fg) measured by quantitative convergent beam electron diffraction (QCBED) were used for validation of different density functional theory (DFT) approximations. Twenty-three Fg the transition metals Cr, Fe, Co, Ni, and Cu, metal based intermetallic phases γ-TiAl, β-NiAl, γ1-FePd using a multi-beam off-zone axis QCBED method then compared with calculated ab initio DFT local approximation (LDA) LDA + U, generalized gradient approximations (GGA) functionals. Different functionals perform very differently materials crystal structures regarding prediction Fg. All GGA tested in paper except EV93 achieve good overall agreement experimentally determined BCC Cr while performs best FCC Ni Cu. The fail to predict accurately β-NiAl γ1-FePd. U approach, through tuning can excellent matches all metallic systems investigated this paper. use accessible low order as an additional set metrics approaches calculations is discussed has potential assist stimulate development improved