  The [C II] 158 micron line is an important emission line diagnostic in
Photodissociation Regions (PDRs), but this emission line can also emerge from
ionized gas. This work calculates the contribution of [C II] emission from
ionized gas over a wide range of parameter space by considering the simplified
case of an H+ region and PDR in pressure equilibrium. Additionally, these
calculations also predict the strong correlation observed between [N II] 205
micron emission and [C II] discussed by previous authors. Overall, the results
of these calculations have wide-ranging applications to the interpretation of
[C II] emission in astrophysical environments.
