Ion Collisions with Water Molecules: A Time-Dependent Density Functional Theory Approach

Collisions of simple ions from water molecules in the energy range of 10-5000 keV/amu are considered within an independent electron model. The basis generator method applied in the past successfully to ion-atom collisions is adapted to deal with molecular targets. Cross sections for single- and multiple-electron processes (capture and transfer to the continuum) are obtained directly from solving time-dependent Kohn-Sham-type orbital equations and using a Slater determinant based analysis. Fragmentation yields are predicted on the basis of a semi-phenomenological model which uses the calculated cross sections as input. Comparison with experiment is made for proton and He+ impact collisions.