galaxies, are undetected [@bergvall-2000]. A detailed study of the neutral gas of the ISM of Haro11 by [@bergvall-2000] investigated the mass budget of the different ISM phases. They establish masses for each phase: M(H [i]{}) $\rm{< 10^{8}~M_{\odot}}$, with an upper limit on the atomic H [i]{}; M(PDR) of $\rm{2~\times~10^{8}~M_{\odot}}$ using the LWS \[C [ii]{}\] observations, the PDR mass being larger than the H [i]{} mass; and $\rm{M(H_{2}) \sim 10^{8}~M_{\odot}}$ for the molecular gas, using both a scaling of the PDR mass and the CO upper limit converted to H$\rm{_{2}}$ column density through the CO/H$\rm{_{2}}$ conversion factor ($X_{\rm CO}$). They used a Galactic value for $X_{\rm CO}$ [@strong-1988]: $X_{\rm CO, gal}=2.3 \times 10^{20}~\rm{cm^{-2}~(K~km~s^{-1})^{-1}}$. Therefore they describe the ISM structure as: very extended PDRs, in which the H [i]{} mass resides; a small fraction of the total ISM gas is left in atomic form; and the bulk of the gas, that is normally in neutral state, is ionised by the starburst. [@bergvall-2002] derive M(H [ii]{}) $\rm{\sim 10^{9}~M_{\odot}}$ from H$\alpha$ observations for the ionised gas. These masses are lower than the total stellar mass of $\rm{10^{10}~M_{\odot}}$ derived in [@adamo-2010].

However, important questions remain, particularly on the state of the ionised, neutral atomic, and 