  This work focuses on [O I] and [C II] emission towards NGC 6334 A, an
embedded H+ region/PDR only observable at infrared or longer wavelengths. A
geometry where nearly all the emission escapes out the side of the cloud facing
the stars, such as Orion, is not applicable to this region. Instead, we find
the geometry to be one where the H+ region and associated PDR is embedded in
the molecular cloud. Constant density PDR calculations are presented which
predict line intensities as a function of AV (or N(H)), hydrogen density (nH),
and incident UV radiation field (G0). We find that a single component model
with AV ~650 mag, nH = 5x10^5 cm-3, and G0 = 7x10^4 reproduces the observed [O
I] and [C II] intensities, and that the low [O I] 63 to 146 micron ratio is due
to line optical depth effects in the [O I] lines, produced by a large column
density of atomic/molecular gas. We find that the effects of a density-law
would increase our derived AV, while the effects of an asymmetric geometry
would decrease AV, with the two effects largely canceling. We conclude that
optically selected H+ regions adjacent to PDRs, such as Orion, likely have a
different viewing angle or geometry than similar regions detected through IR
observations. Overall, the theoretical calculations presented in this work have
utility for any PDR embedded in a molecular cloud.
