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  Willers, T.; Adroja, D.T.; Rainford, B.D.; Hu, Z.; Hollmann, N.; Körner, P.O.; Chin, Y.-Y.; Schmitz, D.; Hsieh, H.H.; Lin, H.-J.; Chen, C.T.; Bauer, E.D.; Sarrao, J.L.; McClellan, K.J.; Byler, D.; Geibel, C.; Steglich, F.; Aoki, H.; Lejay, P.; Tanaka, A.; Tjeng, L.H.; Severing, A.: Spectroscopic determination of crystal-field levels in CeRh₂Si₂ and CeRu₂Si₂ and of the 4f⁰ contributions in CeM₂Si₂ (M=Cu, Ru, Rh, Pd, and Au). Physical Review B 85 (2012), p. 035117/1-8

10.1103/PhysRevB.85.035117

Abstract:
We have determined the ground-statewave functions and crystal-field-level schemes of CeRh₂Si₂ andCeRu₂Si₂ using linear polarized soft x-ray-absorption spectroscopy (XAS) and inelastic neutron scattering. We find large crystal-field splittings and ground-state wave functions which are made of mainly J_z = |±5/2> with some amount of |∓3/2> in both the compounds. The 4f⁰ contribution to the ground state of several members of the CeM₂Si₂ family with M = (Cu, Ru, Rh, Pd, and Au) has been determined with XAS, and the comparison reveals a trend concerning the delocalization of the f electrons. Absolute numbers are extracted from scaling to results from hard x-ray photoelectron spectroscopy on CeRu₂Si₂ by Yano et al. [Phys. Rev. B 77, 035118 (2008)].