Self-diffusion coefficients of methane/n-hexane mixtures at high pressures: An evaluation of the finite-size effect and a comparison of force fields

•Analysis of different force fields on self-diffusion in n-alkanes mixtures.•Finite-size effects on self-diffusivities at high pressures.•Accuracy of the Yeh-Hummer correction using different force fields.•Influence of n-alkane conformation and caging effects on self-diffusion.