# fgcent

Specify the center of the fine grid (in a focusing calculation) based on a molecule’s center or absolute coordinates for mg-para and mg-auto multigrid calculations. The syntax is:

where a user can specify either

`mol {id}`
  Center the grid on molecule with integer ID id; as assigned in the READ section (see READ input file section) of the input file. Molecule IDs are assigned in the order they are read, starting at 1.

or the user can specify

`xcent ycent zcent`
  Center the grids on the coordinates (floating point numbers in Å) at which the grid is centered. Based on the input molecule PDB coordinate frame.