Upper: TPD-IR spectra obtained after the codeposition of CH₃CHO + H (exp. c2) at 10 K. The applied deposition ratio of CH₃CHO:H was 2:40, and the used H-atom flux was 1.2 × 10¹³ atoms cm⁻² s⁻¹ Bottom: (a) TPD-IR difference spectrum for the range from 140 to 170 K obtained after the codeposition of CH₃CHO + H ice mixtures in a ratio of CH₃CHO:H=2:40 at 10 K. (b) Reference spectrum of CH₃CHO. The dashedlines and arrows are shown for the vibrational peaks of the studied molecules. IR spectra are offset for clarity.