Page "Atomic orbital" Paragraph 18

The angular factors of atomic orbitals Θ ( θ ) Φ ( φ ) generate s, p, d, etc.

functions as real combinations of spherical harmonics Y < sub > lm </ sub >( θ, φ ) ( where l and m are quantum numbers ).

There are typically three mathematical forms for the radial functions R ( r ) which can be chosen as a starting point for the calculation of the properties of atoms and molecules with many electrons.