Comment on "Isochoric, isobaric, and ultrafast conductivities of aluminum, lithium, and carbon in the warm dense matter regime"

B B L Witte; G Röpke; P Neumayer; M French; P Sperling; V Recoules; S H Glenzer; R Redmer

doi:10.1103/PhysRevE.99.047201

Comment on "Isochoric, isobaric, and ultrafast conductivities of aluminum, lithium, and carbon in the warm dense matter regime"

Phys Rev E. 2019 Apr;99(4-2):047201. doi: 10.1103/PhysRevE.99.047201.

Authors

B B L Witte^{1

2}, G Röpke¹, P Neumayer³, M French¹, P Sperling^{2

4

5}, V Recoules⁶, S H Glenzer², R Redmer¹

Affiliations

¹ Institut für Physik, Universität Rostock, 18051 Rostock, Germany.
² SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 72 Menlo Park, California 94025, USA.
³ Extreme Matter Institute, GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt, Germany.
⁴ European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany.
⁵ Aible GmbH, Am Vögenteich 24, 18055 Rostock, Germany.
⁶ CEA, DAM, DIF, 91297 Arpajon Cedex, France.

PMID: 31108609
DOI: 10.1103/PhysRevE.99.047201

Abstract

Dharma-wardana et al. [M. W. C. Dharma-wardana et al., Phys. Rev. E 96, 053206 (2017)2470-004510.1103/PhysRevE.96.053206] recently calculated dynamic electrical conductivities for warm dense matter as well as for nonequilibrium two-temperature states termed "ultrafast matter" (UFM) [M. W. C. Dharma-wardana, Phys. Rev. E 93, 063205 (2016)2470-004510.1103/PhysRevE.93.063205]. In this Comment we present two evident reasons why these UFM calculations are neither suited to calculate dynamic conductivities nor x-ray Thomson scattering spectra in isochorically heated warm dense aluminum. First, the ion-ion structure factor, a major input into the conductivity and scattering spectra calculations, deviates strongly from that of isochorically heated aluminum. Second, the dynamic conductivity does not show a non-Drude behavior which is an essential prerequisite for a correct description of the absorption behavior in aluminum. Additionally, we clarify misinterpretations by Dharma-wardana et al. concerning the conductivity measurements of Gathers [G. R. Gathers, Int. J. Thermophys. 4, 209 (1983)IJTHDY0195-928X10.1007/BF00502353].