The model is described in: J.J. Van Laar, The Vapor Pressure of Binary Mixtures, Z. Phys. Chem., 1910, Vol. 72, p. 723.
GEX/(R×T) = a1×a2×x1×x2/(a1×x1 + a2×x2) Parameters determined in TDE are a1 and a2 .
For the symmetric form of the model, a1 = a2.
Temperature dependencies for activity-coefficient model parameters are expressed with: TDE-TSeries1.
Details of the model implementation in TDE, including ThermoML-Equation representation are available. (See the ThermoML web site for details of this IUPAC communication standard.)