Fragmentation of water molecules by proton impact: The role of multiple electron processes

Proton collisions with water molecules are analyzed at impact energies ranging from 20 keV to several MeV to distinguish fragmentation patterns in collisions involving capture and ionization. Solutions of the time-dependent Schr\"odinger equation restricted to an independent-electron model are complemented with a fragmentation model for water molecules. Recent measurements can be explained when electron processes up to triple electron removal are taken into account.