Hi everyone, I've been trying to get a microcanonical (energy conserving, NVE) MD run with periodic boundary conditions. I'm using the provided box of 216 water molecules and the SPC force field (flexible). When I turn PBC off, the energy RMSD is <0.01kJ/mol with a 0.1fs time step (energy is conserved). When PBC is turned on, the energy RMSD is much greater at ~50kJ/mol. Even when I turn off the atomic charges, the energy RMSD is still the same, so I am suspecting that at least the VdW potential switching methods is at fault.
Anyone able to help? Here are the relevant parameters in the mdp file... nstlist = 1 ns_type = grid rlist = 0.9 coulombtype = pme vdwtype = switch rcoulomb = 0.9 rvdw = 0.8 rvdw_switch = 0.5 constraints = none pbc = xyz tcoupl = no gen_vel = yes gen_temp = 300 gen_seed = 173529 Thanks a lot, Lee-Ping _______________________________________________ gmx-users mailing list gmx-users@gromacs.org http://www.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to [EMAIL PROTECTED] Can't post? Read http://www.gromacs.org/mailing_lists/users.php