Direct comparison between the fragments of QMS-TPD spectra in the range from 50 to 225 K obtained after the UV-exposure of 10 ML thick pure HCCH ice at 10 K with >4.6 × 10¹⁶ cm⁻² photons (black empty circles) and the subsequent exposure of this photoprocessed ice with 1.3 × 10¹⁷ cm⁻² H atoms at 10 K (red filled circles). The results obtained upon subtraction of the initial mass spectrum from the mass spectrum obtained upon hydrogenation of the ice for each of the presented m/z values are presented in Appendix A.