All-electron CI calculations of 3d transition-metalL2,3 XANES using zeroth-order regular approximation for relativistic effects

Abstract

X-ray-absorption near-edge structures (XANES) at 3d transition-metal (TM)L2,3 edges are computed using the all-electron configuration interaction (CI) method. Slaterdeterminants for the CI calculations are composed of molecular orbitals obtained bydensity functional theory (DFT) calculations of model clusters. Relativistic effects aretaken into account by the zeroth-order regular approximation (ZORA) usingtwo-component wavefunctions. The theoretical spectra are found to be strongly dependenton the quality of the one-electron basis functions. On the other hand, a different choice ofthe exchange–correlation functionals for the DFT calculations does not exhibit visiblechanges in the spectral shape. Fine details of multiplet structures in the experimental TML2,3 XANES of MnO, FeO and CoO are well reproduced by the present calculations when theone-electron basis functions are properly selected. This is consistent with ourprevious report showing good agreement between theoretical and experimental TML2,3 XANES when four-component relativistic wavefunctions were used.