to describe the actual radiation field incident on a typical region in the Galactic plane, the use of the [[extinguish]{}]{} command is recommended. However, it is also stated that this command should not be used except as a quick test, and a more physical extinction of the continuum may be accomplished by transmitting it through a model of the absorbing slab.

For the sake of simplicity, we assume a uniform density of $1$ cm$^{-3}$ and a total column density of $10^{21}$ cm$^{-2}$, appropriate for the Milky Way disk [@DickeyLockman90]. The main difference between the resulting continua, shown in Figure \[figContinua\], is that the [[extinguish]{}]{} command does not affect the energy band between 0.1 and 1 Rydberg, responsible for molecular Hydrogen photodissociation. When the incident radiation field is propagated through the ISM, many of these ultraviolet photons become absorbed by the dust component and re-emitted in the far infrared.

The details of the interstellar radiation field have a dramatic impact on the vertical structure computed by the code. Figure \[figExtTrans\] compares the results obtained for $n_0=1$ cm$^{-3}$ using the [[extinguish]{}]{} command and those obtained by propagating the [[table ISM]{}]{} field through the uniform slab before reaching the Galactic mid plane. The 