Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

We present experiments investigating dense carbon at pressures between 100 GPa and 200 GPa and temperatures between 5 000K and 15 000 K. High-pressure samples with different temperatures were created by laser-driven shock compression of graphite and varying the initial density from 1.53 g/cm3 to 2.21 g/cm3 and the drive laser intensity from 7.1TW/cm2 to 14.2TW/cm2. In order to deduce temperatures, spectrally resolved X-ray scattering was applied to determine ion-ion structure factors at a scattering vector of k = 4.12 · 1010 m−1, which shows high sensitivity to temperature for the investigated sample conditions. After comparison to corresponding DFT-MD simulations, we were able to assign each structure factor a temperature and use these results to test several theoretical predictions for the melting line of carbon at high pressures.