AM ENDOR STUDY OF RBI-O-2(-)

In this work, an ENDOR analysis of the O-2(-) defect in RbI is present ed. A complete angular variation of one set of Rb-85 and Rb-87 ENDOR t ransitions is shown. The corresponding hyperfine and nuclear quadrupol e coupling tensors are determined. The orientation of the principal ax es of these tensors is in good agreement with the overall D-2h symmetr y of the O-2(-) ion in the crystal. The ENDOR results can only be expl ained assuming a monovacancy model, wherein the O-2(-) molecule is rep lacing a single I- ion. A comparison with a previous ENDOR study of th e S-2(-) centre in RbCl is presented. The linewidth of the EPR signals can be explained using the ENDOR results.