Transport and optical properties of warm dense aluminum in the two-temperature regime: Ab initio calculation and semiempirical approximation

Abstract

This work is devoted to the investigation of transport and optical properties of liquid aluminum in the two-temperature case. At first optical properties, static electrical, and thermal conductivities were obtained in the ab initio calculation which is based on the quantum molecular dynamics, density functional theory, and the Kubo-Greenwood formula. Then the semiempirical approximation was constructed based on the results of our simulation. This approximation yields the dependences σ 1 DC ∝ 1 / Ti0.25 and K ∝ Te / Ti0.25 for the static electrical conductivity and thermal conductivity, respectively, for liquid aluminum at ρ = 2.70 g/cm3, 3 kK ≤ Ti ≤ Te ≤ 20 kK. Our results are well described by the Drude model with the effective relaxation time τ ∝ Ti- 0.25. We have considered a number of other models for the static electrical and thermal conductivities of aluminum, they are all reduced in the low-temperature limit to the Drude model with different expressions for the relaxation time τ. Our results are not consistent with the models in which τ ∝ T i- 1 and support the models which use the expressions with the slower decrease of the relaxation time. © 2014 AIP Publishing LLC.