<font face="tahoma,sans-serif">Hi all,</font><div><font face="tahoma,sans-serif"><br></font></div><div><font class="Apple-style-span" face="tahoma, sans-serif">I'm trying to calculate the force on one particle and the total electrostatic energy of my system, which consists of a lattice of 25 evenly spaced charges in the xy plane and a single charge in the center above to preserve charge neutrality. The reference values I have been given are in dimensionless units, so I am tasked with either converting my output to dimensionless units or having gromacs work in reduced units from the get go. I have set the mass of each charge to 1, the magnitude of the charge on each particle to 1, and the values of the C6 and C12 parameters in my itp file to 4.0, since I'm just using gmx.ff for this (hopefully simple) calculation. I've turned off temperature coupling because this is purely a test of the handling of electrostatics with 3D Ewald summation plus the correction for slab geometry. However, the force and energy I calculate are still quite far from the reference values. Have I missed anything if I want my output to be in dimensionless units? </font></div>
<div><font class="Apple-style-span" face="tahoma, sans-serif"><br></font></div><div><font class="Apple-style-span" face="tahoma, sans-serif">Thanks,</font></div><div><font class="Apple-style-span" face="tahoma, sans-serif">Alex</font></div>