The density profiles of the gas-liquid interface of the three-dimensional Lennard-Jones (12-6) particle system are studied by nonequilibrium molecular dynamics simulation. The system is a rectangular parallelepiped box of the size of Lx ≫ Ly x Lz. Two Nosé-Hoover heat baths with different temperature are attached to the regions near both ends in the x-direction. Heat flows in the system in the x-direction and it maintains the system in a gas-liquid coexisting state. A gas-liquid interface exists steadily in the system box and an asymmetric density profile is observed. We consider the characteristic lengths ξg and ξl in the gas and liquid phase sides defined using density in each phase ρg,l = aξg,l-3, respectively. The sum of the characteristic lengths ξ = ξg + ξl corresponds to the thickness of the interface. Using ξg,l, the density profile in the interface is well described by the tanh form in each phase side ρg,l(x) = ρg,l + β g,l tanh |(x - x0)/ξg,l|. The critical behavior of this model is consistent with the three-dimensional Ising universality.
ASJC Scopus subject areas
- Physics and Astronomy(all)