Growth and Raman spectrum of Ba2Mg(B3O6)2 crystal

Ba2Mg(B3O6)(2) (BMBO) is a potential stimulated Raman scattering (SRS) crystal. In this work, a colorless transparent BMBO single crystal with a dimension of 32x23x7 mm(3) has been grown by the Kyropoulos method. A spontaneous Raman spectrum of the crystal was recorded at room temperature. Site group analysis and first-principles calculations were employed to interpret the Raman spectrum. The site group analysis results show that the total lattice modes are 10A(g)+11A(u)+10E(g)+11E(u), of which 10A(g)+10E(g) are Raman-active. The crystal Raman spectrum was computed in CASTEP (Cambridge Sequential Total Energy Package) using a hybrid method combining density functional perturbation theory with the finite displacement method. All of the Raman-active modes have been identified. The internal modes of the B3O6 ring in the crystal give rise to vibrations with Raman shifts above 220 cm(-1); the translations and the librations of the rings, as well as the translations of the Ba2+ cations, give rise to vibrations with Raman shifts below 220 cm(-1). The strongest peak at 645 cm(-1) in the experimental spectrum is assigned to the breathing mode of the B3O6 ring. (C) 2012 Elsevier B.V. All rights reserved.