Thermo-chemical and thermo-physical properties of the high-pressure phase anhydrous B (Mg14Si5O24): An ab-initio all-electron investigation
-
,
Abstract
Using the hybrid B3LYP density functional method, we computed the ab-initio thermo-chemical and -physical properties of the mineral anhydrous B (Anh-B), which has been recently suggested as a potential phase responsible for the X-discontinuity in the Earth’s mantle at ~300 km depth through the reaction forsterite + periclase = Anh-B, and also to likely split the 410 km discontinuity within the interior of a cold slab through the reaction wadsleyite/ringwoodite = Anh-B + stishovite. We first conducted an investigation of the static properties through a symmetry-preserving relaxation procedure and then computed, on the equilibrium structure, harmonic vibrational modes at the longwavelength limit corresponding to the center of the Brillouin zone (k → 0). While optic modes are the eigenvectors of the Hessian matrix at Γ point, acoustic modes were obtained by solving the non-zero components of the strain matrix. Following the Kieffer model, acoustic branches were assumed to follow sine wave dispersion when traveling within the Brillouin zone. All thermodynamic properties that depend on vibrational frequencies namely, heat capacities, thermal expansion, thermal derivative of the bulk modulus, thermal correction to internal energy, enthalpy, Gibbs free energy, thermal pressure and Debye temperature, were computed on the basis of quasi-harmonic mode-gamma analysis of the volume effects on vibrational frequencies. Moreover, the strain tensor was used to calculate several thermo-physical properties of geophysical interest (transverse and longitudinal wave velocities, shear modulus, Young’s modulus, and Poisson’s ratio). The ab-initio results derived in this study and the available data on molar volumes were used to calculate the univariant equilibrium forsterite + periclase = Anh-B. The results are in satisfactory agreement with the reversed experimental data of Ganguly and Frost (2006).
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Fe site occupancy in magnetite-ulvöspinel solid solutions: A new approach using X-ray magnetic circular dichroism
- Discovery, mineral paragenesis, and origin of wadalite in a meteorite
- Cathodoluminescence microscopy and spectroscopy of synthetic ruby crystals grown by the optical floating zone technique
- Structural relaxation around Cr3+ and the red-green color change in the spinel (sensu stricto)-magnesiochromite (MgAl2O4-MgCr2O4) and gahnite-zincochromite (ZnAl2O4-ZnCr2O4) solid-solution series
- Recrystallization in fully metamict gadolinite from Ytterby (Sweden), annealed in air and studied by 57Fe Mössbauer spectroscopy
- Fantappièite, a new mineral of the cancrinite-sodalite group with a 33-layer stacking sequence: Occurrence and crystal structure
- Reinvestigation of the crystal structure of the zeolite gobbinsite: A single-crystal X-ray diffraction study
- Arsenic-rich fergusonite-beta-(Y) from Mount Cervandone (Western Alps, Italy): Crystal structure and genetic implications
- Crystal structure and low-temperature behavior of “disordered” thomsonite
- Cooling-induced crystallization of microlite crystals in two basaltic pumice clasts
- Crystal structure analyses of four tourmaline specimens from the Cleopatra’s Mines (Egypt) and Jabal Zalm (Saudi Arabia), and the role of Al in the tourmaline group
- Combined single-crystal X-ray and neutron powder diffraction structure analysis exemplified through full structure determinations of framework and layer beryllate minerals
- Olivine crystal size distributions in kimberlite
- Solubility of manganotantalite and manganocolumbite in pegmatitic melts
- The effect of silica on ferric/ferrous ratio in silicate melts: An experimental study using Mössbauer spectroscopy
- HRTEM investigation of trilling todorokite and nano-phase Mn-oxides in manganese dendrites
- Thermo-chemical and thermo-physical properties of the high-pressure phase anhydrous B (Mg14Si5O24): An ab-initio all-electron investigation
- The incommensurately modulated structures of natural natrite at 120 and 293 K from synchrotron X-ray data
- Sulfide oxidation observed using micro-Raman spectroscopy and micro-X-ray diffraction: The importance of water/rock ratios and pH conditions
- In situ measurements of plagioclase growth using SIMS depth profiles of 7Li/30Si: A means to acquire crystallization rates during short-duration decompression events
- Crystal chemistry of the MgAl2O4-MgMn2O4-MnMn2O4 system: Analysis of structural distortion in spinel- and hausmannite-type structures
- The effect of Al and water on the compressibility of diopside
- Geothermometric study of Mg-rich spinels from the Somma-Vesuvius volcanic complex (Naples, Italy)
- Serpentine minerals discrimination by thermal analysis
- A new type of cubic-stacked layer structure in anthoinite, AlWO3(OH)3
- Townendite, Na8ZrSi6O18, a new uranium-bearing lovozerite group mineral from the Ilímaussaq alkaline complex, Southern Greenland
- Letter. Pressure-induced transformations in kaolinite
- Letter. The crystal structure of gypsum-II determined by single-crystal synchrotron X-ray diffraction data
Artikel in diesem Heft
- Fe site occupancy in magnetite-ulvöspinel solid solutions: A new approach using X-ray magnetic circular dichroism
- Discovery, mineral paragenesis, and origin of wadalite in a meteorite
- Cathodoluminescence microscopy and spectroscopy of synthetic ruby crystals grown by the optical floating zone technique
- Structural relaxation around Cr3+ and the red-green color change in the spinel (sensu stricto)-magnesiochromite (MgAl2O4-MgCr2O4) and gahnite-zincochromite (ZnAl2O4-ZnCr2O4) solid-solution series
- Recrystallization in fully metamict gadolinite from Ytterby (Sweden), annealed in air and studied by 57Fe Mössbauer spectroscopy
- Fantappièite, a new mineral of the cancrinite-sodalite group with a 33-layer stacking sequence: Occurrence and crystal structure
- Reinvestigation of the crystal structure of the zeolite gobbinsite: A single-crystal X-ray diffraction study
- Arsenic-rich fergusonite-beta-(Y) from Mount Cervandone (Western Alps, Italy): Crystal structure and genetic implications
- Crystal structure and low-temperature behavior of “disordered” thomsonite
- Cooling-induced crystallization of microlite crystals in two basaltic pumice clasts
- Crystal structure analyses of four tourmaline specimens from the Cleopatra’s Mines (Egypt) and Jabal Zalm (Saudi Arabia), and the role of Al in the tourmaline group
- Combined single-crystal X-ray and neutron powder diffraction structure analysis exemplified through full structure determinations of framework and layer beryllate minerals
- Olivine crystal size distributions in kimberlite
- Solubility of manganotantalite and manganocolumbite in pegmatitic melts
- The effect of silica on ferric/ferrous ratio in silicate melts: An experimental study using Mössbauer spectroscopy
- HRTEM investigation of trilling todorokite and nano-phase Mn-oxides in manganese dendrites
- Thermo-chemical and thermo-physical properties of the high-pressure phase anhydrous B (Mg14Si5O24): An ab-initio all-electron investigation
- The incommensurately modulated structures of natural natrite at 120 and 293 K from synchrotron X-ray data
- Sulfide oxidation observed using micro-Raman spectroscopy and micro-X-ray diffraction: The importance of water/rock ratios and pH conditions
- In situ measurements of plagioclase growth using SIMS depth profiles of 7Li/30Si: A means to acquire crystallization rates during short-duration decompression events
- Crystal chemistry of the MgAl2O4-MgMn2O4-MnMn2O4 system: Analysis of structural distortion in spinel- and hausmannite-type structures
- The effect of Al and water on the compressibility of diopside
- Geothermometric study of Mg-rich spinels from the Somma-Vesuvius volcanic complex (Naples, Italy)
- Serpentine minerals discrimination by thermal analysis
- A new type of cubic-stacked layer structure in anthoinite, AlWO3(OH)3
- Townendite, Na8ZrSi6O18, a new uranium-bearing lovozerite group mineral from the Ilímaussaq alkaline complex, Southern Greenland
- Letter. Pressure-induced transformations in kaolinite
- Letter. The crystal structure of gypsum-II determined by single-crystal synchrotron X-ray diffraction data
