抄録
Energy-minimization calculations with accurate transferable interatomic potentials have been performed to investigate the possible existence of two new high-pressure aluminous phases, MgAl2O4 with the CaFe2O4 structure (called HPCF) and Al2SiO5 with the V3O5 structure (HPVO), both proposed previously based on high-temperature and high-pressure experiments. Of these, the HPCF phase is found to be energetically stable with reasonable nearest-neighbour bond distances. The calculated static compression of HPCF also agrees very well with measured data. In addition the calculated X-ray powder intensities based on the energy-minimized structural parameters for the HPCF phase compare well with experiment. Thus the present energy calculation confirms the existence of the HPCF phase with the CaFe2O4 structure. On the other hand, it is found to be energetically very unlikely that the HPVO phase has the V3O5 structure. The X-ray powder pattern for this phase, calculated based on the energy minimized structural parameters assuming the V3O5 structure, shows no resemblance to experimental data. Hence, the existence of the previously suggested HPVO phase with the V3O5 structure is very questionable.
