From: Bogdan Costescu (bcostescu_at_gmail.com)
Date: Sun May 27 2012 - 07:10:12 CDT

On Sat, May 26, 2012 at 7:27 PM, Andrew DeYoung <adeyoung_at_andrew.cmu.edu> wrote:
> If the Gromacs configuration and trajectory file formats indeed do not
> support the inclusion of charge information

The XTC file format only stores coordinates, in a reduced precision.
The TRR file format stores one or more of coordinates, velocities and
forces, in either single or double precision.
The topology TOP/ITP/etc. files contain (partial) charges as assigned
from the force field or by the user. This is static information.

Whatever you need to represent as dynamic information needs to be
extracted by you and imported into VMD.

Cheers,
Bogdan