Two proposed residual structures originating from the UV photolysis of C₂H₂ ice: (a) low degrees of aromaticity and (b) high degrees of aromaticity. Some of the dissociative ionization fragments are shown in different colors. These substituted functional groups are: m/z=39 (red), m/z=51 (orange), m/z=53 (yellow), m/z=63 (green), m/z=65 (turquoise), m/z=77 (blue), m/z=91 (violet), m/z=115 (lavender), m/z=127 (pink), m/z=201(brown). The molecules are presented in two-dimensional flat structures for simplicity.