<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>Hi,</div><div> I find that in the ffnonbonded.itp under OPLS forcefield ( inside opls.ff directory), for each particle-type, there is a partial charge assigned to it. However, again in the .rtp file, for each residue, under each charge group, each of the atom is assigned </div><div>another partial charge assigned to it. I wonder what are the purposes of having two partial charge entries and which charge is actually being used in simulation . My guess is that , the charge distribution assigned in the .rtp file is most probably the one being used during simulation. If so, then what is the purpose of having another partial charge entry in the ffnonbonded.itp.</div><div>If someone can clarify the doubt, that will be great.</div><div><br></div><div>Sanku</div></div></body></html>