these sequences, there is fine-structure splitting in the ground state and a correspondingly small excitation energy, $\epsilon_N$, giving dielectronic capture into high principal quantum numbers (because of the Rydberg relation $q^2/n^2\le \epsilon_N$). Stabilization is via $n\rightarrow n'$ transitions and the recombined final state is built upon an excited parent. Ultimately, it is the strength of collisional coupling of this final state with the continuum which determines whether recombination or ionization prevails. As the density increases, collisional LTE extends further down the energy spectrum. It is difficult to give a general statement about the position of such final states relative to the ionization limit. So, we assume a worst case scenario, i.e., that such states are subject to suppression, and we use the preceding suppression formula. If density effects are found to be small in photoionized plasmas then this is likely sufficient. If they appear to be significant then a more detailed treatment based on collisional-radiative modeling will be needed. Thus, for these systems, we retain the same suppression formula developed above, that is, $S^N(x,q,T)=S(x,x_a(q,T))$ for $N=\left\{5,6,8,9,13,14,16,17\right\}$, and for all $q$ and $T$.

For the hydrogenic and the closed-shell He-like and Ne-like cases, on the other hand, the excitations proceed via 