Thermal programmed desorption of an irradiated H₂S ice sample. A given m∕z value can correspond to the molecular ion of a species or to a fragment of a larger species. The desorption temperatures of S_x molecules are indicated by the solid vertical lines. Dashed lines indicate the desorption of H₂S_x species. Apart from the molecular ion of each species, the values of the main fragments used to confirm the presence of these species are displayed.