Single and multiple electron removal processes in proton–water-molecule collisions

摘要

Charge-state correlated cross sections for single- and multiple-electron removal processes (capture andnionization) in proton-H2O collisions are calculated by using the nonperturbative basis generator method adaptednfor ion-molecule collisions [Phys. Rev.A80, 060702(R) (2009)]. The results are comparedwith experimental datanfor a wide range of impact energies spanning from 20 keV to several MeV. Single-electron removal probabilitiesnin each molecular orbital are evaluated using the inclusive-probability formalism to predict the yields of chargednfragments (H2O+, OH+, H+, O+) according to branching ratios that are valid at high impact energies. Atnintermediate and low energies, we calculate improved fragmentation cross sections that include the effects ofnmultiple-electron removal processes. The resulting fragmentation yields agree with experiments at the 20%–30%nlevel even below 100 keV impact energy.