Spectroscopic determination of crystal-field levels in CeRh2Si2 and CeRu2Si2 and of the 4f0 contributions in CeM2Si2 (M=Cu, Ru, Rh, Pd, and Au).

We have determined the ground-state wave functions and crystal-field-level schemes of CeRh2Si2 and CeRu2Si2 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 Jz = | ±5/2) with some amount of |∓3/2) in both the compounds. The 4f° 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 derealization 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. 0351IX (2008)]. [ABSTRACT FROM AUTHOR]