Abstract
The paramagnetic rare earth ions Yb3+, Ce3+ and Gd3+ and the transition metal ion Cr3+ were investigated in the cubic elpasolite crystal Cs2NaYF6 with ENDOR. The superhyperfine (shf) interaction parameters of the first 19F, 23Na and 133Cs shells were determined. In the case of Gd3+ they were analyzed in an overlap model of the transferred hyperfine interaction including exchange polarisation.