The triangular-well potential is a representation of the molecular interactions in nature. In this potential the interaction energy decreases as the distance between molecules increases, which is closer to reality than the square-well potential in which the interaction suddenly disappears at a specified distance. Barker and Henderson perturbation theory [1] can be used to calculate the thermodynamic properties for this fluid. Smith et al. [2] have reported some results for the first and second order terms for the triangular well fluid with a well range of twice the hard sphere diameter. In this work, the behavior of the perturbation terms has been evaluated using molecular simulation for well ranges from 1.5 to 4 times the hard sphere diameter.

[1] J.A. Barker, D. Henderson, Rev. Mod. Phys. 48 (1976) 587-671.

[2] W.R. Smith, D. Henderson, J.A. Barker, Can. J. Phys., 53 (1975) 5-12.