Lennard-Jones Energy Parameter for Pure Fluids from Scaled Particle Theory

By considering the fact that the surface tension of a real fluid arises from acombination of both repulsive and attractive forces between molecules, a new expression for theinterfacial tension has been derived from scaled particle theory (spt) based on the work ofcavityformation and the interaction energy between molecules. at the critical temperature, the interfacialtension between coexisting liquid and vapour phases vanishes and the intermolecular attractiveforces must exactly counterbalance the repulsive forces associated with cavity formation. theeffective lennard-jones energy parameter has been calculated by using a simple equation derivedfrom spt for a range ofpure fluids including noble gases, diatomic and triatomic gases, short andmedium length hydrocarbons, aromatic compounds, oxygen containing compounds. the evaluatedlennard-jones energy parameters and reiss's spt theory were used to calculate the surface tensionofpure compounds near critical temperature and were compared with the experimental data. theresults indicated that the developed spt in this work calculates the surface tensions much closer tothe experimental data compared with those reiss's spt theory .