Crystal structure of BaMg2Si2O7 and Eu2+ luminescence

Crystal Structure of BaMg2Si2O7 was determined and refined by a combined powder X-ray and neutron Rietveld method (monoclinic, C2/c, no. 15, Z = 8, a = 7.24553(8) angstrom, b = 12.71376(14) angstrom, c = 13.74813(15) angstrom, beta = 90.2107(8)degrees, V = 1266.44(2) angstrom(3); R-p/R-wp = 3.38%/4.77%). The structure contains a single crystallographic type of Ba atom coordinated to eight O atoms with C-1 (1) site symmetry. Under 325-nm excitation Ba0.98Eu0.02Mg2Si2O7 exhibits an asymmetric emission band around 402 nm. The asymmetric shape of the emission band is likely associated with a small electron-phonon coupling in BaMg2Si2O7 The integrated intensity of the emission band was observed to remain constant over the temperature range 4.2-300 K. (C) 2009 Elsevier Inc. All rights reserved.