Investigations of nuclear quadrupole interaction in BaMgAl10O17 : Eu2+

Local environments of divalent europium ions in beta -lattice of barium mag nesium aluminate, BaMgAl10O17 (BAM) have been investigated using a recently developed ab initio band structure method. This method is a variant of the full potential LMTO method. The reliability of this method for calculating electric field gradient (EFG) was tested in the case of aluminum oxide in corundum structure. The calculated EFGs at both cation and anion sites comp are satisfactorily with those from other ab initio methods and from recent measurements. The nuclear quadrupole coupling constants for Eu2+ calculated by this method at various possible sites in BAM, when compared to recently measured Eu-151 Mossbauer spectroscopy results, suggest three locations fo r Eu2+: a Beevers-Ross site, a mid-oxygen site and an anti-Beevers-Ross sit e. Energetically, the anti-Beevers-Ross site appears to be more stable than the other two sites.