Ionization and electron-capture cross sections for single- and multiple-electron removal from H2O by Li3 + impact

In this work, we report experimental and theoretical ionization and electron-capture cross sections for single-, double- and triple-electron removal from H₂O by Li^{3 +} impact at energies ranging from 0.75 to 5.8 MeV. The experiment was carried out by selecting both the final charge state of the projectile and the ejected fragments in coincidence to obtain cross sections associated with ionization and electron-capture channels. The ionic fragments and the emitted electrons produced under single-collision conditions were collected by a time-of-flight spectrometer with single-hit (e.g., OH⁺+H⁰ ) and double-hit events (e.g., OH⁺+H⁺ ) properly discriminated. For the one- and two-electron removal cases, the calculations based on the basis generator method for orbital propagation agree well with the experiment for most of the collision channels studied. Auger-electron emission after vacancy production in the inner 2 a₁ orbital of H₂O is shown to have a substantial effect on the final charge-state distributions over the entire impact-energy interval.