Practical approximation schemes for calculating partition functions of torsional modes are tested against accurate quantum mechanical results for H(2)O(2) and six isotopically substituted hydrogen peroxides. The schemes are classified on the basis of the type and amount of information that is required. First, approximate one-dimensional hindered-rotator partition functions are benchmarked again...

This research has demonstrated that simple structural and potential models can qualitatively and quantitatively predict properties in dense hydrothermal solutions of sodium chloride and water using molecular dynamics simulation. The PTFxi behavior of simulated model systems at 250 bar and 21 wt % NaCl compared favorably to experimental data from ambient to near-critical temperatures as represen...

The surface tension of heavy n-alkanes is a poorly studied subject. Few data exist and the predictive methods used for their estimation are rather complex or show considerable errors for the higher members of the series. In this work, the corresponding states theory is used to predict the surface tension of the series of the n-alkanes. Two approaches have been followed: the first is a second-or...

A comprehensive mixed-solvent electrolyte model has been extended to calculate liquid– liquid equilibria in water–organic salt systems. Also, it has been applied to calculate phase equilibria and speciation in strongly associating systems such as sulfuric acid/oleum (H2SO4+SO3+H2O) in the entire concentration range. The model combines an excess Gibbs energy model with detailed speciation calcul...

In this work, a Genetic Algorithm boosted Least Square Support Vector Machine model by a set of linear equations instead of a quadratic program, which is improved version of Support Vector Machine model, was used for estimation of 98 pure compounds second virial coefficient. Compounds were classified to the different groups. Finest parameters were obtained by Genetic Algorithm method ...

Calcium chloride is a highly soluble chemical compound involved in variable amounts many natural and industrial environments. The description of its properties mineral-solution equilibrium conditions must cover wide range temperatures compositions, including saline solutions. This article reports an improved model for the thermodynamic accurate CaCl2-H2O system according to Pitzer formalism fro...