When users want to examine the results of a single SCF calculation of a geometry, `1SCF` should be used. `1SCF` can be used in conjunction with `RESTART`, in which case a single SCF calculation will be done, and the results printed.

When `1SCF` is used on its own (that is, `RESTART` is not also used), then derivatives will only be calculated if `GRAD` is also specified.

1SCF is helpful in a learning situation. MOPAC normally performs many SCF calculations, and in order to minimize output when following the working of the SCF calculation, `1SCF` is very useful. See An SCF Calculation for a worked example of an SCF.

When calculating the energies required to form electronic excited states, to avoid geometry reorganization, `1SCF` must be used (see Frank Condon Considerations). This allows the vertical transition energies to be calculated (the Franck-Condon transitions).