[gmx-users] tpbconv -zeroq results all coulombic energies to zero

[BIN ZHANG]

Hi, all:

I was trying to use "tpbconv" to modify the tpr file with the command:
tpbconv -s %s.tpr -nsteps -1 -zeroq -n index -o final.tpr

It basically sets the charge of one group to zero. However, when I  
perform mdrun -rerun, all the coulombic energies are zeros, i.e.,  
Coulomb-(SR), Coul.-recip. This really does not make sense since I  
still have atoms in other groups that are charged. I was using  
gromacs4.0.7.

Has anyone seen this before? What exactly is the correct way to  
zeroize the charge for a group of atoms?

Thanks,
Bin