Comparison of absorption spectra toward G10.62-0.4 obtained with Herschel (p-H₂ O and HF) andwith ALMA (HCO⁺ and HOC⁺) at the same velocity resolution of 1 km s⁻¹. The spectra have been displaced vertically for clarity. The HOC⁺ spectrum is scaled by a factor of 10. The velocity range between − 10 and 10 km s⁻¹ corresponds to the molecular gas associated to the G10.6-0.4 H II region, while the foreground absorption can be seen between 10 and 50 km s⁻¹. Despite the huge difference in angular resolution, the absorption spectra are very similar.