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Magnesium oxide at extreme temperatures and pressures studied with first-principles simulations
- Source :
- The Journal of Chemical Physics, vol 151, iss 21, The Journal of Chemical Physics
- Publication Year :
- 2019
- Publisher :
- Zenodo, 2019.
-
Abstract
- We combine two first-principles computer simulation techniques, path integral Monte-Carlo and density functional theory molecular dynamics, to determine the equation of state of magnesium oxide in the regime of warm dense matter, with densities ranging from 0.35 to 71~g$\,$cm$^{-3}$ and temperatures from 10,000 K to $5\times10^8$~K. These conditions are relevant for the interiors of giant planets and stars as well as for shock wave compression measurements and inertial confinement fusion experiments. We study the electronic structure of MgO and the ionization mechanisms as a function of density and temperature. We show that the L-shell orbitals of magnesium and oxygen hybridize at high density. This results into a gradual ionization of the L-shell with increasing density and temperature. In this regard, MgO behaves differently from pure oxygen, which is reflected in the shape of the MgO principal shock Hugoniot curve. The curve of oxygen shows two compression maxima, while that of MgO shows only one. We predict a maximum compression ratio of 4.66 to occur for a temperature of 6.73 $\times 10^7$ K. Finally we study how multiple shocks and ramp waves can be used to cover a large range of densities and temperatures.<br />12 pages, 9 figures. arXiv admin note: text overlap with arXiv:2001.00985
- Subjects :
- Shock wave
Equation of state
Materials science
FOS: Physical sciences
General Physics and Astronomy
chemistry.chemical_element
Electronic structure
010402 general chemistry
01 natural sciences
7. Clean energy
Molecular physics
Ionization
0103 physical sciences
Physical and Theoretical Chemistry
Inertial confinement fusion
Condensed Matter - Materials Science
010304 chemical physics
Magnesium
Materials Science (cond-mat.mtrl-sci)
Warm dense matter
Physics - Plasma Physics
0104 chemical sciences
Plasma Physics (physics.plasm-ph)
chemistry
13. Climate action
Density functional theory
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- The Journal of Chemical Physics, vol 151, iss 21, The Journal of Chemical Physics
- Accession number :
- edsair.doi.dedup.....aec3882f85b92e647ed0051ebc7832b7