title: Transport properties of lithium hydride at extreme conditions from orbital-free molecular dynamics.
abstract: We have performed a systematic study of lithium hydride (LiH), using orbital-free molecular dynamics, with a focus on mass transport properties such as diffusion and viscosity by extending our previous studies at the lower end of the warm, dense matter regime to cover a span of densities from ambient to 10-fold compressed and temperatures from 10 eV to 10 keV. We determine analytic formulas for self- and mutual-diffusion coefficients, and viscosity, which are in excellent agreement with our molecular dynamics results, and interpolate smoothly between liquid and dense plasma regimes. In addition, we find the orbital-free calculations begin to agree with the Brinzinskii-Landau formula above about 250 eV at which point the medium becomes fully ionized. A binary-ion model based on a bare Coulomb interaction within a neutralizing background with the effective charges determined from a regularization prescription shows good agreement above about 100 eV with the orbital-free results. Finally, we demonstrate the validity of a pressure-based mixing rule in determining the transport properties from the pure-species quantities.
authors.affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: L
authors.initials: L
authors.lastname: Burakovsky
authors.forename: C
authors.initials: C
authors.lastname: Ticknor
authors.forename: J D
authors.initials: JD
authors.lastname: Kress
authors.forename: L A
authors.initials: LA
authors.lastname: Collins
authors.forename: F
authors.initials: F
authors.lastname: Lambert
mesh_terms: D003198:Computer Simulation; D004058:Diffusion; D018020:Lithium Compounds / Q000737:chemistry*; D008956:Models, Chemical; D058626:Plasma Gases / Q000737:chemistry*; D014783:Viscosity
chemical_list: D018020:Lithium Compounds; D058626:Plasma Gases