Dense fluid self-diffusion coefficient calculations using perturbation theory and molecular dynamics

• Autor(a) principal: COELHO,L. A. F.
• Data de Publicação: 1999
• Outros Autores: OLIVEIRA,J. V., TAVARES,F. W.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Chemical Engineering
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66321999000300010
• topic: Smooth-sphere theory; self-diffusion coefficient; molecular dynamics

A procedure to correlate self-diffusion coefficients in dense fluids by using the perturbation theory (WCA) coupled with the smooth-hard-sphere theory is presented and tested against molecular simulations and experimental data. This simple algebraic expression correlates well the self-diffusion coefficients of carbon dioxide, ethane, propane, ethylene, and sulfur hexafluoride. We have also performed canonical ensemble molecular dynamics simulations by using the Hoover-Nosé thermostat and the mean-square displacement formula to compute self-diffusion coefficients for the reference WCA intermolecular potential. The good agreement obtained from both methods, when compared with experimental data, suggests that the smooth-effective-sphere theory is a useful procedure to correlate diffusivity of pure substances.