Using ab initio molecular dynamics simulations, we calculated the physical properties of the five key planetary compounds namely, H, He, H2O, MgSiO3, and Fe.
The properties of materials for the pressure and temperature conditions encountered in planets and exoplanets are mostly unknown due to the high pressures and low temperatures encountered. These studies aim at exploring the physical phenomena taking place as the pressure and temperature increase to the ones encountered in planets and exoplanets with the most advanced quantum mechanical approach. This is provided by performing quantum molecular dynamics studies based on density functional theory developed initially to describe solid systems. As the planetary regime is beyond the conditions that can be reached using laboratory experiments, the paradigm is to validate the method first in a regime where diamond anvil cell (DAC) and high power laser experiments can be performed before performing calculations in the planetary regime.
These comparison with experiments typically involve measurement of equation of states points (EOS), electrical, optical properties in pressure and temperature. Once validated, the calculations are performed over the whole thermodynamical domain relevant to planetary modelling. This involves calculations from normal conditions and including the gas, liquid, solid and plasma regimes using a single simulations procedure provided by ab initio molecular dynamics simulations.
Hydrogen, the element I swear twenty years ago that I would not touch amid the controversy regarding its Hugoniot and the difficulty of ab initio methods at initially reproducing it. Since then three different versions allowing planetary modelling and shock measurements analysis.
- S. Mazevet, A. Licari, F. Soubiran (2020) Benchmarking the ab initio hydrogen equation of state for the interior structure of Jupiter Astronomy and Astrophysics major update of the previous version with significant change for the entropy-important for planetary modelling (data)
- G. Chabrier, S. Mazevet, F. Soubiran (2019) A new equation of state for dense hydrogen-helium mixtures The Astrophysical Journal Extension of the Caillabet et al. ab initio EOS to low and high densities and high temperatures to allow for planetary and stellar modelling (data)
- P. Kowalski, S. Mazevet, D. Saumon, M. Challacombe (2007) Equation of state and optical properties of warm dense helium Phys. Rev. B Ab initio equation of state points and transport properties in a regime found in the atmospheres of cool white dwarfs. (data)
S. Mazevet, A. Licari, G. Chabrier, A. Pothekin (2019) Ab initio based equation of state of dense water for planetary and exoplanetary modelling Astronomy and Astrophysics ab initio calculations and functional form of the free energy to deduce the entropy. Cover all the thermodynamical range needed for planetary modelling. (data)
S. Mazevet, R. Musella, F. Guyot (2019) The fate of planetary cores in giant and ice giant planets Astronomy and Astrophysics High pressure melting curves of MgSiO3 from ab initio simulations. (data)
R. Musella, S. Mazevet, F. Guyot (2019) Physical properties of MgO at deep planetary conditions Phys. Rev. B High pressure melting curve and Eos for the B1 and B2 solid phases up to 100Mbar. (data)
S. Mazevet, T. Tsuchiya, T. Taniuchi, A. Benuzzi, F. Guyot (2015) Melting and metallisation of silica in the cores of giant, ice-giants and super-earths Phys. Rev. B. High pressure melting curve of SiO2 up to 40Mbar. (data)
S. Mazevet, R. Musella, F. Guyot (2019) The fate of planetary cores in giant and ice giant planets Astronomy and Astrophysics High pressure melting curves of Fe from two phases up to 100Mbar using ab initio simulations. (data)
J. Bouchet, S. Mazevet, G. Morard, F. Guyot, R. Musella (2013) Ab initio equation of state of iron up to 15Mbar Phys. Rev. B Eos for the bcc phase. (data)
G. Morard, J. Bouchet, D. Valencia, S. Mazevet, F. Guyot (2011) The melting curve of iron at extreme pressures: implications for planetary cores HEDP high pressure melting curve of iron up to 15Mbar (data)