[lammps-users] LAMMPS with PCFF forcefield and comparison with Material studio

Hi there.
I’m using both Material Studio(MS) and LAMMPS for polymeric bulk structures.
Following the typical process for the linkage of both simulation tools, I make initial amorphous structure using MS and use the result as an input file by transfering using ‘msi2lmp’ tool.
As a comparative study, I’ve calculated and compared potential energy components including vdW and electrostatic. For pure polymer systems, both tools generated identical results for valents terms(bond, angle, dihedral etc). On the other hand, wdW and electrostatic energy component obtained from both tools are quite different. The non-bond summation method for both cases were set exactly the same, atom based cutoff for vdW and ewald summation for electrostatic.
As a tast material, I considered Polypropylene.

Here are the summary of the non-bond energy results.
Here, electrostatic pair term is almost 2300 and long range term is -1300 in lammps

Are your special_bonds settings the same between the 2 codes?
Others have done the comparison you describe and gotten
the same answers.

Steve

2009/8/17 YSH <[email protected]>: