Abstract
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 (2g) 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 (1g) (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.