The Pure Gases' Thermophysical Data Computer Aided Analysis

The computer aided analysis of thermophysical data from electronic databases for pure gases is
developed to investigate the molecular interactions and parameters of clusters. Pure gases may be
used as an advanced platform for Thermodynamics education. This approach is based on the
corresponding to the Mass action law series expansion of thermophysical values by degrees of the
monomer fraction density. Unlike the virial expansion by powers of the total density, the series
expansion terms in this method directly reflect properties of the corresponding cluster fractions. The
internal energy had been selected among thermophysical properties as the most informative for this
method. The thermal analysis of its series expansion coefficients permits to estimate the temperature
dependences of the pair bond parameters, the clusters’ bond energies and equilibrium constants, the
soft structural transitions between dominating isomers of clusters. The application of method to
different pure gases, including noble and molecular gases with van der Waals and polar molecular
interactions, brings unknown clusters’ characteristics for gases under investigation. The thermal
analysis of the ordinary and heavy Water vapors points on no trivial isotopic effects. The
unpredictable growth of the pair bond energy with temperature in Alkanes points on existence in
hydrocarbons of some unknown molecular interaction forces in addition to dispersion forces. Large
values of bond energies for polar molecular clusters open possibilities for alternative methods of their
investigation, including the spectroscopic methods. The complex utilization of the computer added
analysis and spectroscopy methods may be very productive.