Observed PACS spectra (continuum normalized) of the OH transition at 119 μm of IRAS F13352+6402 (top left), IRAS F10091+4704 (top right), IRAS F20036−1547 (bottom left), and IRAS F18216+6419 (bottom right). The origin of the velocity scale corresponds to the OH 119.23 μm transition at the systemic velocity. The vertical lines mark the positions of the ¹⁶OH and ¹⁸OH doublets and the CH⁺(3−2) transition. Two of the systems, IRAS F20036−1547 and IRAS F13352+6402, show evidence of fast (maximum velocity ∼1000 km s⁻¹) molecular outflowing gas, while IRAS F10091+4704 shows evidence of a molecular gas inflow. For QSO IRAS F18216+6419 we do not detect significant levels of absorption or emission in any of the OH features.