High-pressure proton disorder in brucite
-
Mainak Mookherjee
und
Lars Stixrude
Abstract
In this paper we explore the structure and physical properties of brucite over a wide range of pressures with density functional theory using the variable cell-shape plane wave pseudopotential method in the local density (LDA) and generalized gradient (GGA) approximations. We probe the energetics underlying the structure and dynamics of the proton sub-lattice by performing a series of constrained and unconstrained static calculations based on an energetically stable √3×√3×1 super-cell wherein proton locations are related to the 6i Wyckoff sites as opposed to the ideal 2d site. The displacement of the hydrogen atom from the threefold axis increases with increasing pressure. This means that even in the absence of thermal energy, the protons are frustrated and would be expected to exhibit long-range disorder akin to a spin glass. To shed light on the dynamic nature of the proton hopping between the 6i-like sites, we determined the activation energy barrier for such jumps. We found that the energy barrier increases with compression, possibly indicating a transition from dynamic proton disorder at lower pressures to static disorder at higher pressure. We have also investigated the possibility of proton jumps across the interlayer, by determining the potential energy well along the O···O vector. We infer that proton jumps across the interlayer are either severely limited or highly cooperative since we did not find any evidence for a double well along the O···O vector. The absence of a double well along the O···O vector, the evolution of O-H···O distances with compression, and the gradual transition to a symmetric O-H···O configuration, all argue for weak hydrogen bonding in brucite.
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Dana Lecture. Rates of Fe, Mg, Mn, and Ca diffusion in garnet
- An FTIR study of hydrogen in anorthoclase and associated melt inclusions
- First occurrence of iodine in natural sulfosalts: The case of mutnovskite, Pb2AsS3(I,Cl,Br), a new mineral from the Mutnovsky volcano, Kamchatka Peninsula, Russian Federation
- The real topological conÞ guration of the extra-framework content in alkali-poor beryl: A multi-methodological study
- A low-temperature heat-capacity study of synthetic anhydrous Mg-cordierite (Mg2Al4Si5O18)
- Dissolution kinetics of pyrochlore ceramics for the disposition of plutonium
- Oxy-amphibole equilibria in Ti-bearing calcic amphiboles: Experimental investigation and petrologic implications for mantle-derived amphiboles
- Fe2+/Fe3+ charge ordering in contact layers of lamellar magnetism: Bond valence arguments
- Calcic amphibole growth and compositions in calc-alkaline magmas: Evidence from the Motru Dike Swarm (Southern Carpathians, Romania)
- Anomalously high Fe contents in rehomogenized olivine-hosted melt inclusions from oxidized magmas
- The rate of ferrihydrite transformation to goethite via the Fe(II) pathway
- Phase transitions and volumetric properties of cryolite, Na3AlF6: Differential thermal analysis to 100 MPa
- The crystal structure of dissakisite-(La) and structural variations after annealing of radiation damage
- Effects of metal protection coils on thermocouple EMF in multi-anvil high-pressure experiments
- First-principles study of the OH-stretching modes of gibbsite
- In situ X-ray diffraction study of phase transitions of FeTiO3 at high pressures and temperatures using a large-volume press and synchrotron radiation
- High-pressure proton disorder in brucite
- Microhardness, toughness, and modulus of Mohs scale minerals
- Effects of pH, temperature, and aqueous organic material on the dissolution kinetics of meta-autunite minerals, (Na, Ca)2-1[(UO2)(PO4)]2⋅3H2O
- InterstratiÞ ed kaolinite-smectite: Nature of the layers and mechanism of smectite kaolinization
- The kinetics of the α → β transition in synthetic nickel monosulÞ de
- An electron microprobe analysis, secondary ion mass spectrometry, and single-crystal X-ray diffraction study of phlogopites from Mt. Vulture, Potenza, Italy: Consideration of cation partitioning
- Unique W-rich alloy of Os and Ir and associated Fe-rich alloy of Os, Ru, and Ir from California
- Schreyerite, V2Ti3O9: New occurrence and crystal structure
- A cold-sealing capsule design for synthesis of fluid inclusions and other hydrothermal experiments in a piston-cylinder apparatus
- Complete solid-solution between Na3Al2(PO4)3 and Mg3Al2(SiO4)3 garnets at high pressure
Artikel in diesem Heft
- Dana Lecture. Rates of Fe, Mg, Mn, and Ca diffusion in garnet
- An FTIR study of hydrogen in anorthoclase and associated melt inclusions
- First occurrence of iodine in natural sulfosalts: The case of mutnovskite, Pb2AsS3(I,Cl,Br), a new mineral from the Mutnovsky volcano, Kamchatka Peninsula, Russian Federation
- The real topological conÞ guration of the extra-framework content in alkali-poor beryl: A multi-methodological study
- A low-temperature heat-capacity study of synthetic anhydrous Mg-cordierite (Mg2Al4Si5O18)
- Dissolution kinetics of pyrochlore ceramics for the disposition of plutonium
- Oxy-amphibole equilibria in Ti-bearing calcic amphiboles: Experimental investigation and petrologic implications for mantle-derived amphiboles
- Fe2+/Fe3+ charge ordering in contact layers of lamellar magnetism: Bond valence arguments
- Calcic amphibole growth and compositions in calc-alkaline magmas: Evidence from the Motru Dike Swarm (Southern Carpathians, Romania)
- Anomalously high Fe contents in rehomogenized olivine-hosted melt inclusions from oxidized magmas
- The rate of ferrihydrite transformation to goethite via the Fe(II) pathway
- Phase transitions and volumetric properties of cryolite, Na3AlF6: Differential thermal analysis to 100 MPa
- The crystal structure of dissakisite-(La) and structural variations after annealing of radiation damage
- Effects of metal protection coils on thermocouple EMF in multi-anvil high-pressure experiments
- First-principles study of the OH-stretching modes of gibbsite
- In situ X-ray diffraction study of phase transitions of FeTiO3 at high pressures and temperatures using a large-volume press and synchrotron radiation
- High-pressure proton disorder in brucite
- Microhardness, toughness, and modulus of Mohs scale minerals
- Effects of pH, temperature, and aqueous organic material on the dissolution kinetics of meta-autunite minerals, (Na, Ca)2-1[(UO2)(PO4)]2⋅3H2O
- InterstratiÞ ed kaolinite-smectite: Nature of the layers and mechanism of smectite kaolinization
- The kinetics of the α → β transition in synthetic nickel monosulÞ de
- An electron microprobe analysis, secondary ion mass spectrometry, and single-crystal X-ray diffraction study of phlogopites from Mt. Vulture, Potenza, Italy: Consideration of cation partitioning
- Unique W-rich alloy of Os and Ir and associated Fe-rich alloy of Os, Ru, and Ir from California
- Schreyerite, V2Ti3O9: New occurrence and crystal structure
- A cold-sealing capsule design for synthesis of fluid inclusions and other hydrothermal experiments in a piston-cylinder apparatus
- Complete solid-solution between Na3Al2(PO4)3 and Mg3Al2(SiO4)3 garnets at high pressure
