Lattice dynamics of Mg2SiO4

Total energy calculations within the density functional theory (DFT), gener alized gradient approximation and ultrasoft pseudopotentials have been used to investigate structural, dynamical and thermodynamical properties of the high-pressure structure of the magnesium orthosilicate (Mg2SiO4, gamma -sp inel, ringwoodite). The phonon dispersion curves and phonon density of stat es have been calculated using the direct method. The results show agreement with the available experimental Raman data. (C) 2001 Elsevier Science B.V. All rights reserved.