This example merges the SCF orbitals of N and O to get a full valence space for NO. In the simplest case the atomic calculations are performed in the individual separate basis sets, but using the same symmetry (C) as the molecular calculation.
One can also do the atomic calculations in the total basis set, using dummy cards. In this case the procedure is more complicated, since the union of the two orbital spaces is over-complete. The calculation can be done as follows:
a) SCF for the total molecule, orbitals saved to 2100.2
b) SCF for the N atom with dummy basis on the O atom, orbitals saved on 2110.2
c) SCF for the O atom with dummy basis on the N atom, orbitals saved on 2120.2
d) Merge the atomic SCF orbitals. Finally, obtain the virtual orbitals by projecting the merge orbitals out of the SCF orbitals for NO.