Solid Molecular Hydrogen: The Broken Symmetry Phase

1997/03/07 by Jorge Kohanoff, Sandro Scandolo, G. Chiarotti +2
Chemistry · Physics and Astronomy · #Advanced Chemical Physics Studies #Molecular Spectroscopy and Structure #Quantum, superfluid, helium dynamics #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevlett.78.2783

5 pages (twocolumn), 4 Postscript figures. To appear in Phys. Rev. Lett

arxiv created 1997/03/07 · openalex publication_date 1997/04/07 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

By performing constant-pressure variable-cell ab initio molecular dynamics simulations we find a quadrupolar orthorhombic structure of Pca2₁ symmetry for the broken symmetry phase (phase II) of solid H₂ at T\phantom\rule0ex0ex=\phantom\rule0ex0ex0 and P\phantom\rule0ex0ex=\phantom\rule0ex0ex110--150GPa. We present results for the equation of state, lattice parameters, and vibronic frequencies, in very good agreement with experimental observations. Anharmonic quantum corrections to the vibrational frequencies are estimated using available data on H₂ and D₂. We assign the observed modes to specific symmetry representations.

Citations

• X-ray diffraction and equation of state of hydrogen at megabar pressures
• Ultrahigh-pressure transitions in solid hydrogen
• Density-functional approximation for the correlation energy of the inhomogeneous electron gas
• Special points for Brillouin-zone integrations
• On the Possibility of a Metallic Modification of Hydrogen