Abstract
laser heating of solid at pressures between 30 and 80 GPa shows that this compound breaks down to oxygen and diamond along a boundary having a negative slope. This decomposition occurs at temperatures much lower than predicted in theory or inferred from previous experiment. Raman spectroscopy and x-ray diffraction were used as structural probes. At pressures higher than 40 GPa the decomposition is preceded by the formation of a new phase ( -VI). These findings limit the stability of nonmolecular phases to moderate temperatures and provide a new topology of the phase diagram.
- Received 11 January 2001
DOI:https://doi.org/10.1103/PhysRevLett.87.075701
©2001 American Physical Society