High Pressure Raman Study and Phase Transitions of KIO_3 Non-Linear Optical Single Crystals
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Potassium iodate KIO<SUB>3</SUB> single crystal samples have been studied under pressure up to 35 GPa at room temperature. Drastic spectral changes and phase transitions were observed. The first phase transition occurs at 5. 0 GPa characterised by major spectral changes in the Raman bands belonging to the v<SUB>1</SUB>, v<SUB>2</SUB>, and v<SUB>4</SUB> modes. The other phase transitions were found at 8. 7, 15 and 22 GPa. The v<SUB>1</SUB> modes soften with pressure up to 15 GPa The phase that is stable between 15-22 GPa has a higher symmetry than the phases in the lower pressures. The IO<SUB>3</SUB> pyramidal ions may have lost their identity and changed to IO<SUB>6</SUB> octahedra above 22 GPa, as indicated by the changes in the Raman bands of the v<SUB>1</SUB> modes and the new bands in the spectral region between 500-600 cm<SUP>-1</SUP>.
- The Review of High Pressure Science and Technology
The Review of High Pressure Science and Technology 7, 751-753, 1998
The Japan Society of High Pressure Science and Technology