ATOM iupac word real repeat(iupac)
The ATOM command specifies the atoms in a residue. The first word in the ATOM specifies the IUPAC name of the atom. The second word in the atom specification gives the chemical type code as specified in the second operand of the MASS command, see RTF Mass Command. The third operand specifies the partial charge of the atom as a real number.
Finally, the remaining words specify the names of atoms which are to be excluded from non-bonded interactions. Such exclusions are made because they are directly bonded or separated by only two covalent bonds. Note that 1-2 and 1-3 non-bonded exclusions can be constructed automatically at segment generation time, see Nbxmod.