Effect of the Cut-Off Radius of the Interatomic Potential on the Surface Tension of n-Nonane in the SAFT-γ Mie Model

Vapor–liquid surface tension is calculated on the evaporation curve of n-nonane in the SAFT-γ Mie model. The calculations are made via molecular dynamics for temperatures in the range of 410 to 505 K. The effect the cutoff radius of the interparticle interaction potential in the model has on the coefficient of surface tension and the difference between densities of the liquid and vapor phases is studied. An extrapolation algorithm is proposed for estimating surface tension with an uncut potential of interaction. The results are in good agreement with tabular values of surface tension. Extrapolation allows the systematic error of calculations to be estimated, while reducing the computational complexity relative to the direct modeling of a system with a large potential cutoff radius.