Dense Hydrocarbon Structures at Megabar Pressures Journal Article uri icon

DCO ID 11121/5521-7703-1546-5355-CC

is Contribution to the DCO

  • YES

year of publication

  • 2016

abstract

  • The structure, bonding, and other properties of phases in the carbon–hydrogen system over a range of conditions are of considerable importance to a broad range of scientific problems. However, the phase diagram of the C–H system at high pressures and temperatures is still not known. To search for new low-energy hydrocarbon structures, we carried out systematic structure prediction calculations for the C–H system from 100 to 300 GPa. We confirmed several previously predicted structures but found additional compositions that adopt more stable structures. In particular, a C2H4 structure is found that has an indirect band gap, and phonon calculations confirm that it is dynamically stable over a broad pressure range. We also identify more carbon-rich structures that are energetically favorable. The results are important for understanding carbon–hydrogen interactions in high-pressure experiments, dense astrophysical environments and the deep carbon cycle in planetary interiors.

volume

  • 7

issue

  • 20