High pressure Raman study of BaMoO4

The structural stability of polycrystalline BaMoO4 under hydrostatic pressure has been investigated by means of Raman spectroscopy up to 8 GPa. Raman spectra reveal a pressure induced phase transition at similar to5.8 GPa. Upon pressure release the structure reverts to its ambient pressure scheelite (CaWO4) structure with no observable hysteresis. The large number of Raman active modes of the high pressure phase suggests either an increase of the size of the unit cell and/or a non-centrosymmetric structure leading to the activation of the ungerade modes of the scheelite structure. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.