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Available under license: CC BY: Creative Commons Attribution 4.0 International License
Final published version, 394 KB, PDF document
Available under license: CC BY: Creative Commons Attribution 4.0 International License
Final published version
Licence: CC BY: Creative Commons Attribution 4.0 International License
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Quantum Monte Carlo study of the phase diagram of solid molecular hydrogen at extreme pressures
AU - Drummond, Neil D.
AU - Monserrat, Bartomeu
AU - Lloyd-Williams, Jonathan H.
AU - Rios, P. Lopez
AU - Pickard, Chris J.
AU - Needs, R. J.
N1 - Supplementary information available for this article at http://www.nature.com/ncomms/2015/150728/ncomms8794/suppinfo/ncomms8794S1.html
PY - 2015/7/28
Y1 - 2015/7/28
N2 - Establishing the phase diagram of hydrogen is a major challenge for experimental and theoretical physics. Experiment alone cannot establish the atomic structure of solid hydrogen at high pressure, because hydrogen scatters X-rays only weakly. Instead, our understanding of the atomic structure is largely based on density functional theory (DFT). By comparing Raman spectra for low-energy structures found in DFT searches with experimental spectra, candidate atomic structures have been identified for each experimentally observed phase. Unfortunately, DFT predicts a metallic structure to be energetically favoured at a broad range of pressures up to 400[thinsp]GPa, where it is known experimentally that hydrogen is non-metallic. Here we show that more advanced theoretical methods (diffusion quantum Monte Carlo calculations) find the metallic structure to be uncompetitive, and predict a phase diagram in reasonable agreement with experiment. This greatly strengthens the claim that the candidate atomic structures accurately model the experimentally observed phases.
AB - Establishing the phase diagram of hydrogen is a major challenge for experimental and theoretical physics. Experiment alone cannot establish the atomic structure of solid hydrogen at high pressure, because hydrogen scatters X-rays only weakly. Instead, our understanding of the atomic structure is largely based on density functional theory (DFT). By comparing Raman spectra for low-energy structures found in DFT searches with experimental spectra, candidate atomic structures have been identified for each experimentally observed phase. Unfortunately, DFT predicts a metallic structure to be energetically favoured at a broad range of pressures up to 400[thinsp]GPa, where it is known experimentally that hydrogen is non-metallic. Here we show that more advanced theoretical methods (diffusion quantum Monte Carlo calculations) find the metallic structure to be uncompetitive, and predict a phase diagram in reasonable agreement with experiment. This greatly strengthens the claim that the candidate atomic structures accurately model the experimentally observed phases.
U2 - 10.1038/ncomms8794
DO - 10.1038/ncomms8794
M3 - Journal article
VL - 6
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
M1 - 7794
ER -