Liquid structure of shock-compressed hydrocarbons at megabar pressures


Liquid structure of shock-compressed hydrocarbons at megabar pressures

Hartley, N. J.; Vorberger, J.; Döppner, T.; Cowan, T.; Falcone, R. W.; Fletcher, L. B.; Frydrych, S.; Galtier, E.; Gamboa, E. J.; Gericke, D. O.; Glenzer, S. H.; Granados, E.; Macdonald, M. J.; Mackinnon, A. J.; Mcbride, E. E.; Nam, I.; Neumayer, P.; Pak, A.; Rohatsch, K.; Saunders, A. M.; Schuster, A. K.; Sun, P.; van Driel, T.; Kraus, D.

We present ion structure results from hydrocarbons (polystyrene, polyethylene) shock compressed to pressures of up to 190 GPa, inducing rapid melting of the samples. The structure of the resulting liquid is then probed using in situ diffraction by an X-ray free electron laser beam, with precise, reliable diffraction data obtained from single shots. This is the first example of single shot diffraction from low-Z samples dynamically driven into the liquid state. The data agrees well with the structure factors calculated from ab initio simulations, demonstrating their ability to model mixed samples in this state. While the results exclude the possibility of complete carbon-hydrogen demixing at the conditions probed, they also, in contrast to previous predictions, demonstrate that diffraction is not always a sufficient diagnostic for this phenomenon.

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Permalink: https://www.hzdr.de/publications/Publ-27747
Publ.-Id: 27747