Experimental evidence for water formation via ozone hydrogenation on
  dust grains at 10 K
  The formation of water molecules from the reaction between ozone (O3) and
D-atoms is studied experimentally for the first time. Ozone is deposited on
non-porous amorphous solid water ice (H2O), and D-atoms are then sent onto the
sample held at 10 K. HDO molecules are detected during the desorption of the
whole substrate where isotope mixing takes place, indicating that water
synthesis has occurred. The efficiency of water formation via hydrogenation of
ozone is of the same order of magnitude of that found for reactions involving O
atoms or O2 molecules and exhibits no apparent activation barrier. These
experiments validate the assumption made by models using ozone as one of the
precursors of water formation via solid-state chemistry on interstellar dust
grains.
