Ion-ion dynamic structure factor, acoustic modes and equation of state of two-temperature warm dense aluminum

Abstract

The ion-ion dynamical structure factor and the equation of state of warm dense aluminum in a two-temperature quasi-equilibrium state, with the electron temperature higher than the ion temperature, are investigated using molecular-dynamics simulations based on ion-ion pair potentials constructed from a neutral pseudoatom model. Such pair potentials based on density functional theory are parameter-free and depend directly on the electron temperature and indirectly on the ion temperature, enabling efficient computation of two-temperature properties. Comparison with ab initio simulations and with other average-atom calculations for equilibrium aluminum shows good agreement, justifying a study of quasi-equilibrium situations. Analyzing the van Hove function, we find that ion-ion correlations vanish in a time significantly smaller than the electron-ion relaxation time so that dynamical properties have a physical meaning for the quasi-equilibrium state. A significant increase in the speed of sound is predicted from the modification of the dispersion relation of the ion acoustic mode as the electron temperature is increased. The two-temperature equation of state including the free energy, internal energy and pressure is also presented.

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Cited by in corpus (7)

• Efficacy of the Radial Pair Potential Approximation for Molecular Dynamics Simulations of Dense Plasmas
• Transferable Interatomic Potentials for Aluminum from Ambient Conditions to Warm Dense Matter
• Yukawa Friedel-Tail pair potentials for warm dense matter applications
• Kinetic energy functionals and the $N$-representability of the electron pair-density given by the classical map hyper-netted-chain (CHNC) method
• Nonthermal effects in solids after swift heavy ion impact
• Evidence for multiple Liquid-liquid phase transitions in carbon, and the Friedel-ordering of its liquid state
• Simple pair-potentials and pseudo-potentials for warm-dense matter and general applications