1s2p RIXS Calculations for 3d Transition Metal Ions in Octahedral Symmetry

Figure 11

Atomic term scheme with spin-orbit coupling for Ti⁴⁺ (3d⁰) comparing the two-step (1s XAS, 2p XES) 1s2p RIXS and the one-step 2p XAS pathways. The two 1s XAS transitions are separated by the small 3d SOC, Coulomb, and exchange interactions; hence, the splitting is small. The direct dipole transitions in 2p XAS can only populate the final states with , while the dipole decays in 2p XES can reach final states with . However, terms with or 4 cannot be populated in either case and thus do not contribute to the spectrum. Nonaccessible terms are omitted for clarity.