Communication: Formation of slow electrons in the Auger decay of core-ionized water molecules

Double Auger decay of O1s^-1 and its satellite states in H ₂O has been studied with a multi-electron coincidence method, and a process leading to autoionizing O^* fragments has been revealed. The breaking of the two O-H bonds producing the autoionizing O ^* fragments occurs for highly excited H₂O ²⁺ populated by the initial Auger decay. The O^* fragments are more favorably produced in the decay from the satellite states, resulting from the larger population of highly excited H₂O ²⁺ states inheriting the valence excitation in the initial state.