Atomistic molecular dynamics simulation of diffusion in binary liquid n-alkane mixtures.

Well relaxed atomistic configurations of binary liquid mixtures of n-alkanes, obtained via a new Monte Carlo simulation algorithm [Zervopoulou et al., J. Chem. Phys. 115, 2860 (2001)], have been subjected to detailed molecular dynamics simulations in the canonical ensemble. Four different binary systems have been simulated (C[sub 5]–C[sub 78] at T=474 K, C[sub 10]–C[sub 78] at T=458 K, and C[sub 12]–C[sub 60] at T=403.5 and 473.5 K). Results are presented for the diffusion properties of these mixtures over a range of concentrations of the solvent (lighter component). The self-diffusion coefficients of the n-alkanes, calculated directly from the simulations, are reported and compared with the predictions of two theories: the detailed free volume theory proposed by Vrentas and Duda based on the availability of free volume in the blends, and a combined Rouse diffusant and chain-end free volume theory proposed by Bueche and von Meerwall et al. A direct comparison with recently obtained experimental data [von Meerwall et al., J. Chem. Phys. 111, 750 (1999)] is also presented. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]