High pressure Raman spectroscopic study of BaFCl

Raman spectroscopic measurements at different pressures are carried out on BaFCl single crystals using diamond anvil cell up to 25.6 GPa pressure. The tetragonal structure of BaFCl at ambient transforms into a mixture of tetragonal and orthorhombic structures at 10.8 GPa. Both phases exist up to 21.1 GPa. Another phase transition to a monoclinic structure starts at 21.1 GPa. All three phases coexist up to 25.6 GPa. Mode assignment is carried out for the high pressure monoclinic phase. The mode Gruneisen parameters for the ambient tetragonal structure are obtained for four modes.