HR: 0830h
AN: V11D-0526    [PDF]
TI: Quasi-harmonic Predictions Of Structural Parameters At High P,T
AU: Wentzcovitch, R M
EM: wentzcov@cems.umn.edu
AF: Department of Chemical Engineering and Materials Science, Institute of Technology, University of Minnesota, 421 Washington Avenue S. E., Minneapolis,, Minneapolis, MN 55455 United States
AU: Wentzcovitch, R M
EM: wentzcov@cems.umn.edu
AF: Supercomputing Institute for Digital Simulation and Advanced Computation, University of Minnesota, 117 Pleasant St. S. E.,, Minneapolis, MN 55455 United States
AU: * Tsuchiya, J
EM: junt@cems.umn.edu
AF: Department of Chemical Engineering and Materials Science, Institute of Technology, University of Minnesota, 421 Washington Avenue S. E., Minneapolis,, Minneapolis, MN 55455 United States
AU: * Tsuchiya, J
EM: junt@cems.umn.edu
AF: Supercomputing Institute for Digital Simulation and Advanced Computation, University of Minnesota, 117 Pleasant St. S. E.,, Minneapolis, MN 55455 United States
AB: Reliable computations of materials properties at high pressures and temperatures (P,T) is possible as long as one has the essential knowledge of crystal structures and structural parameters at the same conditions. Variable cell shape molecular dynamics enabled ten years ago these computations in complex structures. However, its routine application is still not a reality because of the highly demanding nature of these computations. Besides, this technique should not predictive below the Debye T. Here we introduce a complementary, often alternative, and extremely simple procedure that allows one to determine complex crystal structures from first principles high P,T free energy computations within the quasi-harmonic approximation. We have applied it to predict the structure of MgSiO$_3$-perovskite up to 4000 K and 150 GPa and have successfully tested it against available crystallographic data.
DE: 3909 Elasticity and anelasticity
DE: 3919 Equations of state
DE: 3924 High-pressure behavior
DE: 3939 Physical thermodynamics
DE: 3949 Thermal expansivity
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting