D. Schaniel, P. Allenspach, A. Furrer, K. Krämer and H. U. Güdel
Dimer Splitting of Er³⁺ in Cs₃Er₂Br₉
J. Alloys Comp. 323-324, 481-485 (2001)                 

Abstract: Inelastic neutron scattering (INS) measurements were performed on the rare earth dimer compound Cs₃Er₂Br₉. The crystalline electric field (CEF) parameters were determined. The lack of any exchange splitting associated with the CEF transitions can be explained by the lare single ion anisotropy for Er. An energy level scheme is proposed, which was tested with extensive magnetization and specific heat measurements as a function of temperature and magnetic field.