Reactions of Hydrated Electrons (H 2 O) n − with Carbon Dioxide and Molecular Oxygen: Hydration of the CO 2 − and O 2 − Ions

The gas‐phase reactions of hydrated electrons with carbon dioxide and molecular oxygen were studied by Fourier transform ion cyclotron resonance (FT‐ICR) mass spectrometry. Both CO 2 and O 2 react efficiently with (H 2 O) n − because they possess low‐lying empty π* orbitals. The molecular CO 2 − and O 2 − anions are concurrently solvated and stabilized by the water ligands to form CO 2 − (H 2 O) n and O 2 − (H 2 O) n . Core exchange reactions are also observed, in which CO 2 − (H 2 O) n is transformed into O 2 − (H 2 O) n upon collision with O 2 . This is in agreement with the prediction based on density functional theory calculations that O 2 − (H 2 O) n clusters are thermodynamically favored with respect to CO 2 − (H 2 O) n . Electron detachment from the product species is only observed for CO 2 − (H 2 O) 2 , in agreement with the calculated electron affinities and solvation energies.