The Helmholtz energy F is written as the sum F = F-H + F-A + F-Pol, where F-H is the hard-body contribution, F-A the attractive dispersion force contribution, and F-Pol either rite quadrupolar or dipolar contribution. Here, a new, expression for F-A is constucted by a simultaneous correlation of experimental data of methane, oxygen, and ethane. The resulting equations for F with only three or four substance-specific parameters are tested for several nonpolar, quadrupolar, and dipolar fluids. rn the correlation of large data sets good results are obtained. The significance of the approach, however is in the good to excellent prediction of all thermodynamic properties ill the whole fluid region based on a parameter fit to only four experimental data-two vapor pressures and two saturated liquid densities.