Try out our program for fitting our group’s equation of state (which is based on a lattice model for chain molecules) to Pressure-Volume-Temperature data for polymer melts as well as small molecules too.  The goal here is to obtain the molecular characterization parameters: “r” – the number of segments per chain molecule, “v” – the volume per lattice site, and “epsilon” – the near neighbor non bonded segment-segment interaction energy.

This is a very simple-to-use Mathematica program.  You can down load the program here. You will get a folder that contains the Mathematica fitting program itself, along with a sub-folder containing several files of PVT data and a “readme” file describing the data and the source.