Compressibility and Structural Properties of Jadeite, NaAlSi2O6 at High Pressure

The structural properties of jadeite at high pressures (0.000 1-30 GPa) are investigated using plane-wave pseudopotential density functional theory method. As a function of pressure, the monoclinic cell parameters were calculated and the compressibility coefficients are 0.002 6, 0.002 3 and 0.002 6 GPa(-1), respectively. The bond length, bond angle and distortion variation were studied in order to obtain the information of polyhedral compression. The pressure-volume equation of state was considered in order to obtain the bulk modulus K-0. Comparison between the calculated K-0 values and the experimental data suggested that the model provides reasonable insights into crystallographic and physical properties of jadeite.