A uniform source-and-sink scheme developed by Cao and Li (2010) for calculating the thermal conductivity of solid argon was applied to calculation of the self-diffusion coefficient. The particles were divided into equal halves. By exchanging the labels of individual atoms from the right and left half systems, an internal matter flux could be produced; constituting an internal matter source and sink. The density profile was piecewise quadratic throughout the system and the self-diffusion coefficient could be easily extracted from the mean densities of the right and left half systems rather than by fitting the density profile. In particular, this was a non-equilibrium molecular dynamics method but established on an equilibrium system. The scheme was used to calculate the self-diffusion coefficient by taking a Lennard-Jones fluid as a case, examining its homogeneity, convergence, label exchange interval, and dependence on density, temperature, and system size.

Application of the Uniform Source-and-Sink Scheme to Molecular Dynamics Calculation of the Self-Diffusion Coefficient of Fluids. Dong, R.Y., Cao, B.Y.: International Journal for Numerical Methods in Engineering, 2012, 92[3], 229-37