Abstract
ENDOR measurements have been made on the linear bond structure Cr3+-F--Cd2+ in crystals of CsCdF3:Cr3+. The observed hyperfine interactions with the 19F, 111Cd and 113Cd nuclei indicate that the unpaired spin fractions in 2psigma and 2ppi orbitals on the F- ion are fsigma =-0.1% and fpi =4.3%. The value of fsigma , about which there has been some uncertainty in the literature, is considerably smaller than recent estimates.