fix_modify AtC atom_weight <method> <arguments>
- <method> = 
 value: atoms in specified group assigned constant value given
 lattice: volume per atom for specified lattice type (e.g. fcc) and parameter
 element: element volume divided among atoms within element
 region: volume per atom determined based on the atom count in the MD regions and their volumes. Note: meaningful only if atoms completely fill all the regions.
 group: volume per atom determined based on the atom count in a group and its volume
 read_in: list of values for atoms are read-in from specified file
 
 fix_modify atc atom_weight constant myatoms 11.8  
  fix_modify atc atom_weight lattice  
  fix_modify atc atom_weight read-in atm_wt_file.txt  
 
Command for assigning the value of atomic weights used for atomic integration in atom-continuum coupled simulations. 
Use of lattice option requires a lattice type and parameter is already specified. 
lattice