Ground state structure of high-energy-density polymeric carbon monoxide
Physical Review B
American Physical Society
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Xia, K., Sun, J., Pickard, C., Klug, D., & Needs, R. (2017). Ground state structure of high-energy-density polymeric carbon monoxide. Physical Review B, 95 (14. 144102)https://doi.org/10.1103/PhysRevB.95.144102
Crystal structure prediction methods and first-principles calculations have been used to explore low-energy structures of carbon monoxide (CO). Contrary to the standard wisdom, the most stable structure of CO at ambient pressure was found to be a polymeric structure of $Pna2_1$ symmetry rather than a molecular solid. This phase is formed from six-membered (four carbon + two oxygen) rings connected by C=C double bonds with two double-bonded oxygen atoms attached to each ring. Interestingly, the polymeric $Pna2_1$ phase of CO has a much higher energy density than trinitrotoluene (TNT). On compression to about 7 GPa, $Pna2_1$ is found to transform into another chainlike phase of $Cc$ symmetry which has similar ring units to $Pna2_1$. On compression to 12 GPa, it is energetically favorable for CO to polymerize into a purely single bonded $Cmca$ phase, which is stable over a wide pressure range and transforms into the previously known $Cmcm$ phase at around 100 GPa. Thermodynamic stability of these structures was verified using calculations with different density functionals, including hybrid and van der Waals corrected functionals.
J.S. is grateful for financial support from the MOST of China (Grants No. 2016YFA0300404 and No. 2015CB921202), the NSFC (Grants No. 51372112 and No. 11574133), the NSF of Jiangsu Province (Grant No. BK20150012), the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (the second phase), the Fundamental Research Funds for the Central Universities, and the Open Fund of the Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education (INMD-2016M01). C.J.P. and R.J.N. acknowledge financial support from the Engineering and Physical Sciences Research Council (EPSRC) of the UK under Grants No. EP/G007489/2 (C.J.P.) and No. EP/J017639/1 (R.J.N.). C.J.P. is also supported by the Royal Society through a Royal Society Wolfson Research Merit Award. Some of the calculations were performed on the supercomputer in the High Performance Computing Center of Nanjing University and “Tianhe-2” at National Supercomputer Center in Guangzhou.
External DOI: https://doi.org/10.1103/PhysRevB.95.144102
This record's URL: https://www.repository.cam.ac.uk/handle/1810/264498