Quantum molecular dynamics simulations for the nonmetal-metal transition in shocked methane

Quantum molecular dynamics simulations for the nonmetal-to-metal transition in fluid helium.

We have performed quantum molecular dynamics simulations for dense helium to study the nonmetal-to-metal transition at high pressures. We present new results for the equation of state and the Hugoniot curve in the warm dense matter region. The optical conductivity is calculated via the Kubo-Greenwood formula from which the dc conductivity is derived. The nonmetal-to-metal transition is identifi...

Molecular-dynamics simulations of methane hydrate dissociation.

Nonequilibrium molecular-dynamics simulations have been carried out at 276.65 K and 68 bar for the dissolution of spherical methane hydrate crystallites surrounded by a liquid phase. The liquid was composed of pure water or a water-methane mixture ranging in methane composition from 50% to 100% of the corresponding theoretical maximum for the hydrate and ranged in size from about 1600 to 2200 w...

Long Range Corrections to the Vapor-Liquid Equilibrium and Surface Tension of Methane with NVT Molecular Dynamics Simulations

Quantum molecular dynamics simulations of the thermophysical properties of shocked liquid ammonia for pressures up to 1.3 TPa.

We investigate via quantum molecular-dynamics simulations the thermophysical properties of shocked liquid ammonia up to the pressure 1.3 TPa and temperature 120,000 K. The principal Hugoniot is predicted from the wide-range equation of state, which agrees well with the available experimental measurements up to 64 GPa. Our systematic study of the structural properties demonstrates that the liqui...

Superadiabatic Transition Histories in Quantum Molecular Dynamics

We study the dynamics of a molecule’s nuclear wave-function near an avoided crossing of two electronic energy levels, for one nuclear degree of freedom. We derive the general form of the Schrödinger equation in the n-th superadiabatic representation for all n ∈ N, and give some partial results about the asymptotics for large n. Using these results, we obtain closed formulas for the time develop...