Energy transport in Lennard-Jones particle system

Energy transport phenomena in Lennard-Jones particle systems are studied using nonequilibrium simulation with molecular dynamics method. Thermal conductivity in finite size system κ(L) converges with a simple 1/√L in gas, liquid and solid phases. Lennard-Jones particle system reproduced normal thermal conduction which is described by Fourier's heat law. The κ(L) decreases by 10% from the macroscopic thermal conductivity at L ̃ 1100 in gas phase, L ̃ 80 in liquid phase, and L ̃ 150 in solid phase. To describe and understand the microscopic origin of the nonequilibrium thermal conduction, we study the microscopic energy flux carried by a single particle j and its distribution. When steady heat flux flows in the system, the distribution of j is distorted along the direction of the energy flux. The nonequilibrium distribution is described by the equilibrium distributions with different two temperatures. When the system is in nonlinear response region, the distribution has a form different from the one of linear response region even though the global temperature profile reproduces a linear form.