Hi all,
I am using LAMMPS and the msi2lmp tool to generate input files.
I have a system with several polymer chains and recently came across with
the need to tag the molecules and get their ID via the dump command.
I found out that the "ReadCarFile.c" from the msi2lmp tool does not read correctly the
molecule ID. In case someone else wants to do the same, please modify the "ReadCarFile.c"
from line 128 to 136 as shown below. It worked for me 
fscanf(CarF,"%s %lf %lf lf *s %d %s %s %f", (line 128)
         atoms[k].name,
         &(atoms[k].x[0]),
         &(atoms[k].x[1]),
         &(atoms[k].x[2]),
         &(atoms[k].molecule),
         atoms[k].potential,
         atoms[k].element,
         &(atoms[k].q));
     }
Best,
Simao Pereira
University of Trieste (Italy)