Structural and vibrational properties of methane up to 71 GPa

  title={Structural and vibrational properties of methane up to 71 GPa},
  author={Maxim Bykov and Elena Bykova and Chris J. Pickard and Miguel Martinez-Canales and Konstantin Glazyrin and Jesse S. Smith and Alexander F. Goncharov},
  journal={Physical Review B},
Earth and Planets Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road Washington D.C., USA Howard University, 2400 6 St NW, Washington DC 20059, USA Department of Materials Sciences & Metallurgy, University of Cambridge, Cambridge, UK Advanced Institute for Materials Research, Tohoku University, Aoba, Sendai, 980-8577, Japan School of Physics & Astronomy, The University of Edinburgh, Edinburgh, UK Photon Sciences, Deutsches Electronen Synchrotron (DESY), D-22607 Hamburg… 

Figures and Tables from this paper


Dissociation of methane under high pressure.
The pressure-temperature phase diagram is computed, which sheds light into the seemingly conflicting observations of the unusually low formation pressure of diamond at high temperature and the failure of experimental observation of dissociation at room temperature.
Structure and compression of crystalline methane at high pressure and room temperature
Methane, CH4, crystallizes in the face‐centered cubic metal structure (space group Fm3m) at 15.9 kbar and 20 °C. Cubic unit‐cell edges at 16.1, 28.9, 39.5, and 52.1 kbar are 5.4434, 5.3064, 5.1963,
Formation of diamonds in laser-compressed hydrocarbons at planetary interior conditions
The effects of hydrocarbon reactions and diamond precipitation on the internal structure and evolution of icy giant planets such as Neptune and Uranus have been discussed for more than three
The crystal structure of methane B at 8 GPa--an α-Mn arrangement of molecules.
The substructure of phase B of methane at a pressure of ∼8 GPa is determined to be cubic with space group I4¯3m and 58 molecules in the unit cell, which is a factor of √2 larger than had been proposed by Umemoto et al.
Superionic and metallic states of water and ammonia at giant planet conditions.
The phase diagrams of water and ammonia were determined by constant pressure ab initio molecular dynamic simulations at pressures (30 to 300 gigapascal) and temperatures (300 to 7000 kelvin) of relevance for the middle ice layers of the giant planets Neptune and Uranus to improve the understanding of the properties of the middle icy layers.
X-ray diffraction studies and equation of state of methane at 202 GPa
Solid methane (CH(4)) was compressed up to 202 GPa at 300 K in a diamond-anvil cell. The crystal structure and equation of state over this entire range were determined from angle dispersive X-ray
Dissociation of Methane into Hydrocarbons at Extreme (Planetary) Pressure and Temperature
Constant-pressure, first-principles molecular dynamic simulations were used to investigate the behavior of methane at high pressure and temperature, and suggest that, below 100 gigapascals, methane dissociates into a mixture of hydrocarbons, and it separates into hydrogen and carbon only above 300 gigapascalals.
Carbon precipitation from heavy hydrocarbon fluid in deep planetary interiors.
It is argued that reduced mantle fluids precipitate diamond upon re-equilibration to lighter species in the upwelling mantle, and geophysical models of Uranus and Neptune require reassessment because chemical reactivity of planetary ices is underestimated.
Laser-heating diamond anvil cell studies of simple molecular systems at high pressures and temperatures
Abstract We report the application of new laser-heating techniques and sample preparation procedures for simple molecular materials (diatomic molecules and water) under high pressure in the diamond
Phase changes of solid methane under high pressure up to 86 GPa at room temperature
Abstract High pressure studies of solid methane were performed using diamond anvil cells in the pressure range of 0.5–86 GPa. X-ray diffractometry and Raman spectroscopy revealed two high pressure