Dependence of GCEMC simulations of nitrogen adsorption on activated carbons on input parameters Original Research Article

GCEMC molecular simulations of adsorption of nitrogen at 77 K in model, slit-shaped carbon pores show that variations in pore structural parameters and Lennard–Jones parameters have significant effects. Increasing pore wall atom density shifts isotherms to lower pressures, more markedly for monolayer formation than for condensation at higher pressures. Similar effects are found on increasing pore wall thickness, n, especially from n=1 to 2. Values of n≥5 are effectively the same as n=∞. Variations of the Lennard–Jones parameters, ϵff and σff, by ±20% about the reference values have considerable effects on adsorption isotherms obtained from molecular simulations. The pressure ranges for monolayer formation and condensation decrease with increasing molecular size, σff, by nearly three orders of magnitude, and by almost two orders of magnitude with increases in the potential function ϵff. Reduced densities at monolayer completion and at saturation also decrease when ϵff and σff increase. This shows that the selection of Lennard–Jones parameters for molecular simulations should be made with care and the influence of possible errors should be considered.