RAIR spectra obtained after the deposition of C₂H₂ + CO + H (exp. 1.0), C₂H₂ + H (exp. 1.2), 1-propanol (exp. 2.0), CH₃OH (5 × 10¹⁵ cm⁻²), propanal (exp. 2.3), H₂CO (5 × 10¹⁵ cm⁻²), C₂H₆ (5 × 10¹⁵ cm⁻²), and C₂H₂ + CO (exp. 1.1) on a 10 K surface. The spectrum of C₂H₆ is adapted from the work by Öberg et al. (2009). The dashed and dotted lines highlight the frequencies that correlate to the strongest features of propanal and 1-propanol, respectively. Spectra are scaled to highlight the IR features of interest, and are offset for clarity.