High-Pressure Raman Study of Phase Transitions in Solid Bromoform

Abstract

The Raman spectra of solid bromoform and bromoform-d have been measured up to 100 kbar at 300 K in a gasketed diamond anvil cell. The pressure dependence of six intramolecular and three intermolecular vibrations has been investigated in comparison with the Raman results of a low-temperature solid at atmospheric pressure. The α→β and the β→γ phase transition at respective pressures 10 and 42 kbar are presented by the high-pressure behavior of the ν₃ intramolecular mode and the intermolecular vibrations. The mixing state of the β and the γ phase was found at pressures between 34 and 55 kbar. The γ phase metastable at atmospheric pressure becomes stable at high pressures above 42 kbar.