CHARMM-formatted PSF files

[resal81]

From here:

The fields in the atom section [of a PSF file] are atom ID, segment name, residue ID, residue name, atom name, atom type, charge, mass, and an unused 0. PSF files may be in either CHARMM or X-PLOR format, with the CHARMM format using an integer rather than a name for the atom type. NAMD requires the X-PLOR format, which is also more flexible since it is not tied to the specific order of atom types in a single parameter file. NAMD and VMD require that the order of atoms in any PDB, DCD, or other atomic data file exactly matches the order found in the PSF file.