Warm Dense Matter Calculations using OFMD Warm Dense Matter Calculations using OFMD

Orbital-free molecular dynamics is used to perform calculations for aluminum in the warm dense matter regime. The dynamic structure factor obtained from the orbital-free calculations are compared with the dynamic structure factor obtained from pseudo-atom molecular dynamics calculations. These comparisons are made at 5, 20, and 50 eV for wavenumbers that span the single particle, generalized hydrodynamic, and hydrodynamic regimes. While the dynamic structure factors for warm dense aluminum from the pseudoatom molecular dynamics framework have previously been compared with those from the orbital-free framework, these comparisons could only be performed up to 5 eV due to limitations in the pseudopotential used in the orbital free calculations. The orbital-free calculations performed in this project, however, self consistently calculate the pseudopotential and are valid at the higher temperatures of 20 and 50 eV. Good agreement is found between the pseudo-atom molecular dynamics and orbital-free dynamic structure factors in the single particle regime at all three temperatures. In the generalized hydrodynamic and hydrodynamic regimes the ion-acoustic resonance for the orbital-free calculation is slightly higher and appears at a lower energy than that of the pseudo-atom molecular dynamics calculations, but the shape of the curves matches well.