1) First, run IGMPlot using the param.igm and mol.wfx files.
--> it will generate two more files : mol-dgIntra.gnu
    and mol-dgInter.gnu.

2) Make sure to have installed the gnuplot environment
on your computer and then use these gnuplot scripts 
by typing in the terminal:

gnuplot mol-dgIntra.gnu

This will color the 2D-plot dg=f(rho) with the value of qg,
revealing the peaks of the interaction signature.
