FBSD Simulation of Supercritical Argon

A nearly classical fluid, supercritical argon at T=183 K and a density of 1.15 g cm-3 was modeled using a simulation box of 108 atoms interacting through Lennard-Jones potentials with periodic boundary conditions. The real part of the FBSD result is in reasonably good agreement with the classical result, but there is a non-negligible imaginary part. The latter leads to a notable asymmetry of the frequency-dependent transport coefficient.

Velocity correlation function for supercritical argon. Red line: real part of FBSD result. Blue line: imaginary part of FBSD result. Green line: correlation function obtained via classical molecular dynamics.

Fourier transform of the correlation function for supercritical argon. The red line shows the FBSD result. The observed asymmetry arises from the imaginary part of the correlation function. The blue line shows the classical result.