Analyzing the Local Electronic Structure of Co 3 O 4 Using 2p3d Resonant Inelastic X-ray Scattering.

We present the cobalt 2p3d resonant inelastic X-ray scattering (RIXS) spectra of Co 3 O 4 . Guided by multiplet simulation, the excited states at 0.5 and 1.3 eV can be identified as the 4 T 2 excited state of the tetrahedral Co 2+ and the 3 T 2 g excited state of the octahedral Co 3+ , respectively. The ground states of Co 2+ and Co 3+ sites are determined to be high-spin 4 A 2 ( T d ) and low-spin 1 A 1 g ( O h ), respectively. It indicates that the high-spin Co 2+ is the magnetically active site in Co 3 O 4 . Additionally, the ligand-to-metal charge transfer analysis shows strong orbital hybridization between the cobalt and oxygen ions at the Co 3+ site, while the hybridization is weak at the Co 2+ site.