Abstract
We present a simple but accurate equation of state for double Yukawa fluids based on the variational series mean spherical approximation (VSMSA). This allows us to investigate the vapour-liquid equilibrium and its related thermodynamic properties. The comparisons with computer simulation results of the Lennard-Jones (LJ) potential suggest the importance of treating the attractive tail of the potential accurately via VSMSA. The estimated reduced critical parameters T
C
= 1.342, ρ
C
= 0.29 and P
C
= 0.135 are in good agreement with other theoretical and computer simulation results for the LJ system.