Infrared spectra of the codeposition experiments. Panel a: comparison between the final infrared spectra after deposition of a pure H₂S ice (black) superimposed by the final spectrum after codeposition of H₂S and H atoms (red) with analogous experimental conditions. Panel b: infrared spectra acquired during the warming up of the H₂S ice codeposited with H atoms, offset for clarity. In both panels, the assignments of the H₂S and H₂S₂ vibrational bands are shown with dashed lines.