Structures of solid hydrogen at 300K

Abstract

We present results predicting experimentally measurable structural quantities from molecular dynamics studies of hydrogen. In doing this, we propose a paradigm shift for experimentalists -- that the predictions from such calculations should be seen as the most likely hypotheses. Specifically, the experimental results should be aiming to distinguish between the candidate low-energy structures, rather than aiming to solve the simplest structure consistent with the data. We show that the room temperature X-ray diffraction patterns for hydrogen phases I, III, IV and V are very similar, with only small peaks denoting symmetry-breaking from the hcp Phase I. Because they incorporate atomic displacements the XRD patterns implied by molecular dynamics calculations are very different from those arising from the static minimum enthalpy structures found by structure searching. Simulations also show that within Phase I the molecular becomes increasingly confined to the basal plane and suggest the possibility of an unusual critical point terminating the Phase I-III boundary line.

References in corpus (6)

• Observation of the Wigner-Huntington Transition to Solid Metallic Hydrogen
• Density functional theory study of phase IV of solid hydrogen
• Hexagonal structure of phase III of solid hydrogen
• Stacking Characteristics of Close Packed Materials
• Quadrupole Arrangements and the Ground State of Solid Hydrogen
• Efficacious calculation of Raman spectra in high pressure hydrogen

Cited by in corpus (5)

• Understanding high pressure hydrogen with a hierarchical machine-learned potential
• Nuclear Spin Crossover in Dense Molecular Hydrogen
• Two state model for critical points and the negative slope of the melting-curve
• Deep variational free energy prediction of dense hydrogen solid at 1200K
• GW space-time method: Energy band-gap of solid hydrogen