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12Complex Systems of Charged Particles and their Interactions with Electromagnetic Radiation 2018
METASTABLE STATES OF PLASMA PHASE TRANSITION
Norman G. E., Saitov I. M., Sartan R.A.
JIHT RAS, Moscow, Russia
Warm dense hydrogen is investigated by ab initio molecular dynamics simulations in the region of fluid-fluid phase transition. The simulation is performed within the framework of density functional theory. The metastable states of two isotherms of 700 and 1000 K are calculated. The existence of metastability is a strong criterion that the transition is a first order transition.
Modeling of metastable states is an unexplored problem so far. There are two main points that let us to obtain the metastability: the selection of particular initial configurations (coordinates and velocities of ions) and turning off the thermostat. We managed to obtain molecular phase far beyond the phase transition. The metastable branch of the isotherm overlaps the equilibrium branch by density at the interval that is several times more than density jump at the phase transition. The pressure range of metastabilty studied is more than 0.3 Mbar for 1000 K and 0.47 Mbar. The pair correlation function conserves its shape along the 1000 K isotherm that confirms the preservation of the molecular phase.
The work is funded by grant of Russian Foundation for Basic Research 16-08-01218(A), grant of President of Russian Federation for young scientists MK-3231.2017.2 and program of the Presidium of the Russian Academy of Sciences No. 13 "Thermal physics of high energy densities".
the Presidium of the Russian Academy of Sciences No. 13 "Thermal physics of high energy densities".
