ENDOR AND TRANSFERRED HYPERFINE INTERACTION OF IMPURITY RARE-EARTH IONS WITH NEAREST DIAMAGNETIC IONS IN CRYSTALS

The tetragonal Er3+ ion associated with the interstitial F- ion along the [100] axis in CaF2 is studied using ENDOR. The parameters of the t ransferred hyperfine interaction and of the nuclear Zeeman interaction of the surrounding fluorine ions are determined. Anomalously large va lues of the pseudo-nuclear Zeeman effect on the F- nuclei are found. T he theoretical analysis of these parameters is carried out in a frame of operator techniques in the theory of transferred hyperfine interact ions. A number of useful relations for practical calculations of the v alues of the local field at ligand nuclei are reported.