Photon-induced desorption of several photoproducts during irradiation of a pure ethanol ice in experiment 2, see Table 3. Results were similar in experiment 1. Irradiation intervals are indicated with vertical dashed lines. Signal due to rotation of the sample holder between irradiation intervals were omitted. a) Phochemidesorption of formaldehyde/ethane (see text) observed with mass fragments m/z = 29 and m/z = 30. b) Photochemidesorption of water and ethane observed with mass fragments m/z = 18 and m/z = 27, respectively. DIET photodesorption was detected for CO and CH₄ (m/z = 28 and m/z = 15, respectively). Ion currents of different mass fragments are offset for clarity.