Raman and x-ray diffraction investigations on BaMoO4 under high pressures

X-ray diffraction and Raman scattering studies on the scheelite structured barium molybdate show that, at similar to 5.8 GPa, it undergoes a first order phase transition to the fergusonite structure (I2/a, Z = 4)-as also observed in iso-structural barium tungstate. At still higher pressures, barium molybdate transforms to another phase between similar to 7.2 and 9.5 GPa. On release of pressure from 15.8 GPa, the initial phase is recovered, implying that the observed structural modifications are reversible.