Quadrupole interactions in the rhenium apatite Ba10(ReO5)6Cl2 observed by time-differential perturbed angular correlation (TDPAC)

Abstract TDPAC measurements on the 356–81 keV γ-γ cascade of 133 Cs in the 133 Ba-labelled halogenoapatite Ba 10 (REO 5 ) 6 C1 2 , containing pyramidal ReO 5 groups, have been performed at room temperature. Two static electric quadrupole interactions are observed corresponding to the two coordination sites of barium. The measured electric field gradient (EFG) values are compared with values calculated using a point-charge model.