title: Atomic diffusion in solid molecular hydrogen.
abstract: We performed ab initio molecular dynamics simulations of the C2c and Cmca-12 phases of hydrogen at pressures from 210 to 350 GPa. These phases were predicted to be stable at 0 K and pressures above 200 GPa. However, systematic studies of temperature impact on properties of these phases have not been performed so far. Filling this gap, we observed that on temperature increase diffusion sets in the Cmca-12 phase, being absent in C2c. We explored the mechanism of diffusion and computed melting curve of hydrogen at extreme pressures. The results suggest that the recent experiments claiming conductive hydrogen at the pressure around 260 GPa and ambient temperature might be explained by the diffusion. The diffusion might also be the reason for the difference in Raman spectra obtained in recent experiments.
authors.affiliation: Condensed Matter Theory, Department of Theoretical Physics, AlbaNova University Center, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden. anatoly@kth.se
authors.forename: Anatoly B
authors.initials: AB
authors.lastname: Belonoshko
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ramzan
authors.forename: Ho-Kwang
authors.initials: HK
authors.lastname: Mao
authors.forename: Rajeev
authors.initials: R
authors.lastname: Ahuja
mesh_terms: D003198:Computer Simulation; D004058:Diffusion; D006859:Hydrogen / Q000737:chemistry*; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D011312:Pressure; D013696:Temperature
chemical_list: D006859:Hydrogen
references.citation: Nat Mater. 2011 Nov 13;10(12):927-31
references.pmid: 22081083
references.citation: Nature. 2000 Feb 10;403(6770):632-5
references.pmid: 10688193
references.citation: Phys Rev Lett. 2012 Mar 23;108(12):125501
references.pmid: 22540596
references.citation: Phys Rev B Condens Matter. 1996 Oct 15;54(16):11169-11186
references.pmid: 9984901
references.citation: J Chem Phys. 2012 Aug 21;137(7):074501
references.pmid: 22920125
references.citation: Phys Rev B Condens Matter. 1985 Jul 1;32(1):381-389
references.pmid: 9936676
references.citation: Phys Rev Lett. 1996 Oct 28;77(18):3865-3868
references.pmid: 10062328
references.citation: Phys Chem Chem Phys. 2011 Nov 28;13(44):19979-87
references.pmid: 21993402
references.citation: Proc Natl Acad Sci U S A. 2001 Dec 4;98(25):14234-7
references.pmid: 11717391
references.citation: Nature. 2004 Oct 7;431(7009):669-72
references.pmid: 15470423
references.citation: Nature. 2002 Apr 11;416(6881):613-7
references.pmid: 11948345
references.citation: Phys Rev Lett. 2013 Jan 11;110(2):025903
references.pmid: 23383917
references.citation: Phys Rev B Condens Matter. 1994 Dec 15;50(24):17953-17979
references.pmid: 9976227
references.citation: Phys Rev B Condens Matter. 1990 Jun 1;41(16):10963-10971
references.pmid: 9993515
references.citation: Phys Rev Lett. 2008 Apr 18;100(15):155701
references.pmid: 18518124
references.citation: Phys Rev Lett. 2003 May 2;90(17):175701
references.pmid: 12786081