Elasticity of Hydrogen at High Pressures

Monday, 14 December 2015
Poster Hall (Moscone South)
Alexander F Goncharov1, Frederic Decremps2, Michel Gauthier2, Simon Ayrinhac2, Daniele Antonangeli3, Yu. A. Freiman4, Alexei Grechnev4 and S. M. Tretyak4, (1)Carnegie Institution for Science Washington, Washington, DC, United States, (2)CNRS - Sorbonne Universités, IMPMC, Paris, France, (3)CNRS, Paris Cedex 16, France, (4)B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, Kharkov, Ukraine
High-pressure elastic properties of hydrogen give insight into anisotropy, equation of state, thermodynamic properties, and intermolecular potentials of this material providing an important link to ultrahigh pressure behavior approaching transformation to metallic monatomic or molecular state. Here we present picosecond acoustics measurements of compressional sound velocities [1] combined with optical interferometry and Raman spectroscopy of H2 and D2 at 295 K up to 55 GPa. Using the equation of state determined previously [2], we deduced the transverse sound velocities and the Poisson’s ratio up to 55 GPa. The latter shows a broad minimum near 45 GPa (c.f. Ref. [3]) providing a new experimentally proven insight into lattice dynamics of hydrogen at high pressure that can be compared to theoretical calculations of various levels [4].

[1] F. Decremps, M. Gauthier, S. Ayrinhac, L. Bove, L. Belliard, B. Perrin, M. Morand, G. Le Marchand, F. Bergame, J. Philippe, Ultrasonics, 56 (2015) 129-140.

[2] P. Loubeyre, R. LeToullec, D. Hausermann, M. Hanfland, R.J. Hemley, H.K. Mao, L.W. Finger, Nature, 383 (1996) 702-704.

[3] C.-s. Zha, T.S. Duffy, H.-k. Mao, R.J. Hemley, Phys. Rev. B, 48 (1993) 9246-9255.

[4] Y.A. Freiman, A. Grechnev, S.M. Tretyak, A.F. Goncharov, E. Gregoryanz, Fizika Nizkikh Temperatur, 41 (2015) 571.