Temperature-dependent Raman scattering spectra of CsBi(MoO4)2 Original Research Article

Successive phase transitions in CsBi(MoO4)2 at 125 and 325 K have been studied by Raman spectroscopy. The changes in the crystal structure, induced by the low-temperature first-order transition, have been discussed. The found anomalous shifts of some internal modes towards lower frequency with decreasing temperature have been explained as a result of strengthening of double or single oxygen bridges. The present results also provide information on the origin of the unknown phase, identified recently in CsDy(MoO4)2.