High-pressure melting curve of hydrogen

• The melting curve of hydrogen was computed for pressures up to 200 GPa, using molecular dynamics. The inter- and intramolecular interactions were described by the reactive force field (ReaxFF) model. The model describes the pressure-volume equation of state solid hydrogen in good agreement with experiment up to pressures over 150 GPa, however the corresponding equation of state for liquid deviates considerably from density functional theory calculations. Due to this, the computed melting curve, although shares most of the known features, yields considerably lower melting temperatures compared to extrapolations of the available diamond anvil cell data. This failure of the ReaxFF model, which can reproduce many physical and chemical properties (including chemical reactions in hydrocarbons) of solid hydrogen, hints at an important change in the mechanism of interaction of hydrogen molecules in the liquid state.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

density functional theory

equations of state

high-pressure effects

hydrogen

melting

molecular dynamics method

Materials science

Teknisk materialvetenskap

Physics

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