Worked examples, failures included.

Real systems, real numbers, and an honest account of where each model stopped being trustworthy. The limitations sections are the point — anyone can publish the run that worked.

• Molecular dynamicsCohesive energy density of PE/PP meltsAll-atom LAMMPS simulations of polyethylene, polypropylene and a 50/50 blend. The two solubility parameters differ by less than half a percent — and that tells you almost nothing about whether they mix.LAMMPSOPLS-AACohesive energy densityFlory–Huggins
• Molecular dynamicsElastic constants of amorphous polyethyleneAn atomistic simulation reproduced the density of amorphous PE to within half a percent and overestimated its stiffness by more than an order of magnitude. The trajectory data says exactly why.Materials StudioCOMPASS IIIForciteElastic constants