Blog
About

7
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Demixing instability in dense molten MgSiO3 and the phase diagram of MgO.

      1 ,

      Physical review letters

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The phase diagrams of MgSiO3 and MgO are studied from first-principles theory for pressures and temperatures up to 600 GPa and 20,000 K. Through the evaluation of finite-temperature Gibbs free energies, using density-functional theory within the generalized gradient approximation as well as with hybrid exchange-correlation functionals, we find evidence for a vast pressure-temperature regime where molten MgSiO3 decomposes into liquid SiO2 and solid MgO, with a volume change of approximately 1.2%. The demixing transition is driven by the crystallization of MgO--the reaction only occurs below the high-pressure MgO melting curve. The predicted transition pressure at 10,000 K is in close proximity to an anomaly reported in recent laser-driven shock experiments of MgSiO3. We also present new results for the high-pressure melting curve of MgO and its B1-B2 solid phase transition, with a triple point at 364 GPa and 12,000 K.

          Related collections

          Author and article information

          Journal
          Phys. Rev. Lett.
          Physical review letters
          1079-7114
          0031-9007
          Mar 29 2013
          : 110
          : 13
          Affiliations
          [1 ] Department of Physics, Dalhousie University, Halifax, Nova Scotia, Canada B3H 3J5.
          Article
          10.1103/PhysRevLett.110.135504
          23581337

          Comments

          Comment on this article