Low Temperature Physics: 39, 423 (2013); https://doi.org/10.1063/1.4807043 (4 pages)
Физика Низких Температур: Том 39, Выпуск 5 (Май 2013), c. 548-551    ( к оглавлению , назад )

Sound velocities in solid hydrogen under pressure

Yu.A. Freiman, Alexei Grechnev, and S.M. Tretyak

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
E-mail: freiman@ilt.kharkov.ua

Alexander F. Goncharov and Russell J. Hemley

Geophysical Laboratory, Carnegie Institution of Washington 5251 Broad Branch Road NW, Washington DC 20015, USA

Received January 18, 2013

Аннотация

We present results of semi-empirical lattice dynamics calculations of the sound velocities in solid hydrogen under pressure based on the many-body intermolecular potential and first-principle density-functional theory (DFT). Both the sound velocities and elastic moduli are in excellent agreement with data from Brillouin scattering measurements while Silvera–Goldman and Hemley–Silvera–Goldman potentials tend to overestimate the sound velocity. It is shown that the stiffer is the potential the greater is overestimated the sound velocity. As was the case for equation of state and Raman-active lattice phonon calculations, the employed many-body potential works well for phases I and II (up to ~ 140 GPa while for higher pressures the use of the DFT is preferable.

PACS: 64.30.Jk Equations of state of nonmetals;
PACS: 67.80.F– Solids of hydrogen and isotopes;
PACS: 78.30.Am Elemental semiconductors and insulators.

Ключевые слова: solid hydrogen, sound veloсity, density-functional theory.