The structure of liquid carbon elucidated by in situ X-ray diffraction
D. Kraus, J. Rips, Maximilian Schörner, M.G. Stevenson, Jan Vorberger, D. Ranjan, J. Lütgert, B. Heuser, J. H. Eggert, Hanns‐Peter Liermann, Ivan Oleynik, Silvia Pandolfi, R. Redmer, A. Sollier, C. Strohm, Travis J. Volz, B. Albertazzi, S. J. Ali, L. Antonelli, Carsten Baehtz, Orianna B. Ball, Saumyabrata Banerjee, A. B. Belonoshko, C. A. Bolme, V. Bouffetier, R. Briggs, Khachiwan Buakor, Thomas Butcher, Valerio Cerantola, Julien Chantel, A. L. Coleman, J. Collier, G. W. Collins, A. J. Comley, T. E. Cowan, G. Cristoforetti, Hyunchae Cynn, Adrien Descamps, Andrea Di Cicco, S. Di Dio Cafiso, F. Dorchies, M. J. Duff, Anand Dwivedi, Chris Edwards, Daniel Errandonea, Sergey Galitskiy, Eric Galtier, Hélène Ginestet, L. A. Gizzi, A. E. Gleason, S. Göde, Joseph M. Gonzalez, M. G. Gorman, M. Harmand, N. J. Hartley, P. G. Heighway, Cristina Hernandez–Gomez, Andrew Higginbotham, Hauke Höppner, Rachel J. Husband, T. M. Hutchinson, Huijeong Hwang, David A. Keen, Jaeyong Kim, P. Koester, Zuzana Konôpková, A. Krygier, L. Labate, Alejandro Laso García, Amy Lazicki, Yongjae Lee, Paul Mason, M. Masruri, Bernhard Massani, E. E. McBride, J. McHardy, D. McGonegle, C. P. McGuire, R. S. McWilliams, Sébastien Merkel, G. Morard, Bob Nagler, M. Nakatsutsumi, Kien Nguyen-Cong, A.-M. Norton, Norimasa Ozaki, Christoph Otzen, D. J. Peake, A. Pelka, K. A. Pereira, Jonathan Phillips, Clemens Prescher, Thomas R. Preston, Lisa Randolph, A. Ravasio, David Santamarı́a-Pérez, Daniel J. Savage, M. Schoelmerich, Jan‐Patrick Schwinkendorf, Saransh Singh
Abstract
Abstract Carbon has a central role in biology and organic chemistry, and its solid allotropes provide the basis of much of our modern technology 1 . However, the liquid form of carbon remains nearly uncharted 2 , and the structure of liquid carbon and most of its physical properties are essentially unknown 3 . But liquid carbon is relevant for modelling planetary interiors 4,5 and the atmospheres of white dwarfs 6 , as an intermediate state for the synthesis of advanced carbon materials 7,8 , inertial confinement fusion implosions 9 , hypervelocity impact events on carbon materials 10 and our general understanding of structured fluids at extreme conditions 11 . Here we present a precise structure measurement of liquid carbon at pressures of around 1 million atmospheres obtained by in situ X-ray diffraction at an X-ray free-electron laser. Our results show a complex fluid with transient bonding and approximately four nearest neighbours on average, in agreement with quantum molecular dynamics simulations. The obtained data substantiate the understanding of the liquid state of one of the most abundant elements in the universe and can test models of the melting line. The demonstrated experimental abilities open the path to performing similar studies of the structure of liquids composed of light elements at extreme conditions.