HR: 1340h
AN: MR23C-1518    [Abstracts]
TI: An efficient method for computing high PT elascticity by first principles
AU: * Wu, Z
EM: wuzq@cems.umn.edu
AF: Department of Chemical Engineering and Materials Science and Minnesota Supercomputer Institute, 421 Washington Ave SE, Minneapolis, MN 55455, United States
AU: Wentzcovitch, R M
EM: wentzcov@cems.umn.edu
AF: Department of Chemical Engineering and Materials Science and Minnesota Supercomputer Institute, 421 Washington Ave SE, Minneapolis, MN 55455, United States
AB: First principles quasiharmonic (QHA) free energy computations play a very important role in mineral physics because they can predict accurately the structure and thermodynamic properties of materials at pressure and temperature conditions that are still challenging for experiments. They also enable calculations of thermoelastic properties by obtaining the second derivatives of the free energies with respect to Lagrangian strains. However, these are demanding computations requiring 100 to 1000 medium size jobs. Here we introduce and test an approximate method that requires only calculations of static elastic constants, phonon VDOS, and mode Gruneisen parameters for unstrained configurations. This approach is computationally efficient and decreases the computational time by more than one order of magnitude. The human workload is also reduced substantially. We test this approach by computing high PT elasticity of MgO and forsterite. We show one can obtain very good agreement with full first principles results and experimental data. Research supported by NSF/EAR, NSF/ITR (VLab), and MSI (U of MN)
DE: 1011 Thermodynamics (0766, 3611, 8411)
DE: 3611 Thermodynamics (0766, 1011, 8411)
DE: 3919 Equations of state
DE: 3924 High-pressure behavior
DE: 8411 Thermodynamics (0766, 1011, 3611)
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting