otter.ion_orbital_form_factors

otter.ion_orbital_form_factors(aa: Mapping[str, Any], *, r: ndarray, k: ndarray) → ndarray[source]

Transform each existing \(n^{\rm ion}_{nl}(r)\) on the QOZ grid.

Pass one species’ electronic result and the complete, uncropped r and k arrays from the ionic result. The returned (l, n_index, k) array uses the same level ordering as aa['bound_energy_ha']; unused slots are zero. It includes FD occupations, degeneracy, M(E), and f_cut already present in ion_orbital_density_r. No new orbital, SCF, or HNC calculation is performed. TF has no orbitals and is not supported here.

The interpolation and DST-I are the same linear operations as the total n_ion -> f_k workflow, so summing over levels recovers that total to floating-point precision. Do not normalize individual form factors to an integer occupation or apply a separate screening-charge correction.