Calculations for ion-impact induced ionization and fragmentation of water molecules

Charge-state correlated cross sections for single- and multiple-electron removal processes in proton-water-molecule collisions are calculated by using the non-perturbative basis generator method adapted for ion-molecule collisions [1,2]. A fragmentation model is then applied to calculate the yields of $\rm H_2O^+$, $\rm OH^+$, $\rm H^+$, and $\rm O^+$ ions emerging after $\rm H_2O^{q+}$ formation [3]. A detailed comparison is made with experimental data from three groups covering the energy range from 20--5000 keV. It is found that multiple electron processes with $q\le 3$ play an important role at the lower end of this range and are calculated accurately within an independent particle model. We are currently completing the analogous analysis for He$^+$-$\rm H_2O$ collisions for which the presence of the projectile electron poses some additional challenges. \\[4pt] [1] H.J. L\"udde et al, Phys. Rev. A 80, 060702(R) (2009)\\[0pt] [2] M. Murakami et al, Phys. Rev. A 85, 052704 (2012)\\[0pt] [3] M. Murakami et al, Phys. Rev. A 85, 052713 (2012)