The size of the normal output file can become very large when large systems are being used. This can make it difficult to find interesting information. To reduce the amount of information printed to the output file, add OUTPUT to the keyword list.
To allow some blocks of data that would otherwise be suppressed by OUTPUT use OUTPUT followed by letters in parentheses, Allowed letters are
| Letter | Does not suppress |
| C | Coordinates |
| F | Force matrix (in a FORCE calculation) |
| G | Gradients |
| N | Normal coordinates (in a FORCE calculation) |
| O | Orientation (in a FORCE calculation) |
| P | Atomic Orbital Populations |
| Q | Fractional atomic charges |
| T | Topography (atom connectivity) |
| V | Starting velocity of atoms in a DRC/IRC |
| X | Cartesian coordinates |
Thus, if fractional atomic charges are to be printed, but other voluminous data suppressed, use OUTPUT(Q). If atomic orbital populations are also wanted, use OUTPUT(QP). Note that OUTPUT only suppresses output. If some data would not normally be printed, for example, in a 1SCF calculation the gradients would not be printed unless GRADIENTS was also present, then adding letters to the OUTPUT keyword to not suppress the gradients would do nothing.