First-principles multi-electron calculations for L(2,3) ELNES/XANES of 3d transition metal monoxides.

A computational method having quantitatively predictive performance of L(2,3) ELNES/XANES of 3d transition metal (TM) compounds without any empirical parameter is given. Calculations are made on three TM monoxides with rock salt structures, MnO, FeO and CoO using model clusters composed of a TM ion with six coordinating oxide ions. Multi-electron wavefunctions are expressed by a linear combination of Slater determinants made by fully relativistic molecular orbitals for TM-2p, 3d and O-2p. Relative intensity and positions of subpeaks are in excellent agreement to experimental spectra. Our analyses of multi-electron eigenstates found that these subpeaks originate not from different one electron configurations but entirely from the multiplet effects. The dependence of the branching ratio on the formal number of 3d electrons agrees with that of an empirical atomic multiplet theory reported in literature.