Electron-ion and ion-ion potentials for modeling warm-dense-matter: applications to laser-heated or shock-compressed Al and Si

Abstract

The pair-interactions U_{ij}(r) determine the thermodynamics and linear transport properties of matter via the pair-distribution functions (PDFs), i.e., g_{ij}(r). Great simplicity is achieved if U_{ij}(r) could be directly used to predict material properties via classical simulations, avoiding many-body wavefunctions. Warm dense matter (WDM) is encountered in quasi-equilibria where the electron temperature $T_e$ differs from the ion temperature T_i, as in laser-heated or in shock-compressed matter. The electron PDFs g_{ee}(r) as perturbed by the ions are used to evaluate fully non-local exchange-correlation corrections to the free energy, using Hydrogen as an example. Electron-ion potentials for ions with a bound core are discussed with Al and Si as examples, for WDM with T_e \ne T_i, and valid for times shorter than the electron-ion relaxation time. In some cases the potentials develop attractive regions, and then become repulsive and `Yukawa-like' for higher $T_e$. These results clarify the origin of initial phonon-hardening and rapid release. Pair-potentials for shock-heated WDM show that phonon hardening would not occur in most such systems. Defining meaningful quasi-equilibrium static transport coefficients consistent with the dynamic values is addressed. There seems to be no meaningful `static conductivity' obtainable by extrapolating experimental or theoretical σ(ω, T_i, T_e) to ω\to 0, unless T_i \to T_e as well. Illustrative calculations of quasi-static resistivities R(T_i,T_e) of laser-heated as well as shock-heated Aluminum and Silicon are presented using our pseudopotentials, pair-potentials and classical integral equations. The quasi-static resistivities display clear differences in their temperature evolutions, but are not the strict ω\to 0 limits of the dynamic values.

12 pages, 6 figues, Latex files

References in corpus (5)

• All-Electron Path Integral Monte Carlo Simulations of Warm Dense Matter: Application to Water and Carbon Plasmas
• Quantum corrections and bound-state effects in the energy relaxation of hot dense Hydrogen
• Temperature-Dependent Behavior of Confined Many-electron Systems in the Hartree-Fock Approximation
• Numerical solution of shock and ramp compression for general material properties
• Quantum Potential for Diffraction and Exchange Effects

Cited by in corpus (11)

• Electronic Density Response of Warm Dense Matter
• First principles simulations of dense hydrogen
• Ion-ion dynamic structure factor, acoustic modes and equation of state of two-temperature warm dense aluminum
• Efficacy of the Radial Pair Potential Approximation for Molecular Dynamics Simulations of Dense Plasmas
• Equation of state, phonons, and lattice stability of ultra-fast warm dense matter
• A critical assessment of models of pair-interactions and screening used in analyzing recent warm-dense matter (WDM) experiments
• Pair potentials for warm dense matter and their application to x-ray Thomson scattering in aluminum and beryllium
• Yukawa Friedel-Tail pair potentials for warm dense matter applications
• Quantifying errors of the electron-proton/muon correlation functionals through the Kohn-Sham inversion of a two-component model system
• Two-temperature pair potentials and phonon spectra for simple metals in the warm dense matter regime
• Simple pair-potentials and pseudo-potentials for warm-dense matter and general applications