High-pressure Raman spectroscopy of solid oxygen

Abstract
High-pressure Raman spectroscopy of solid oxygen has been carried out at room temperature up to 110 GPa in order to study the recently observed structural transition at 96 GPa. The vibron and lattice phonons in the ɛ-O2 phase corresponding to the transition became undetectable, although the vibron wave number in the ɛ-O2 phase has shown a linear pressure dependence with a coefficient of 2.33 cm1/GPa and reached 1753 cm1 at 94 GPa. Several bands have been recently observed above 25 GPa, and three of them we assigned to higher-order bands.