Polymorphous Transformations in Alkaline-Earth Silicates

Authors

Jianjun Liu, University of Nebraska - Lincoln
Chun-Gang Duan, University of Nebraska at OmahaFollow
Wai-Ning Mei, University of Nebraska at OmahaFollow
R. W. Smith, University of Nebraska at OmahaFollow
John R. Hardy, University of Nebraska - LincolnFollow

Date of this Version

3-2002

Comments

Published in J. Chem. Phys., Vol. 116, No. 9, 1 March 2002. Copyright © 2002 American Institute of Physics. Used by permission.

Abstract

Structural phase transitions in Ca₂SiO₄ and Sr₂SiO₄ are investigated by molecular dynamics simulations. The simulations are based on the potentials calculated from the Gordon–Kim modified electron gas formalism extended to molecular ions. We successfully reproduced the transition γ -α’_H and β-α’_L - α’_H - α in Ca₂SiO₄, and the transition β-α’ in Sr₂SiO₄. We find that the α’_L phase of Ca₂SiO₄ is an ax3b x c superstructure of the α’_H phase, while the α’_H phase has a β-K₂SO₄ structure, and the a phase of Ca₂SiO₄ has a disordered structure with space group P6₃ /mmc.