Eur. Phys. J. D (2016) 70: 82
https://doi.org/10.1140/epjd/e2016-70097-5

Regular Article

An independent-atom-model description of ion-molecule collisions including geometric screening corrections

¹ Institut für Theoretische Physik, Goethe-Universität, 60438 Frankfurt, Germany
² Department of Physics and Astronomy, York University, Toronto, M3J 1P3 Ontario, Canada

^a e-mail: tomk@yorku.ca

Received: 12 February 2016
Received in final form: 3 March 2016
Published online: 12 April 2016

Abstract

A new model to account for geometric screening corrections in an independent-atom-model description of ion-molecule collisions is introduced. The ion-molecule cross sections for net capture and net ionization are represented as weighted sums of atomic cross sections with weight factors that are determined from a geometric model of overlapping cross section areas. Results are presented for proton collisions with targets ranging from diatomic to complex polyatomic molecules. Significant improvement compared to simple additivity rule results and in general good agreement with experimental data are found. The flexibility of the approach opens up the possibility to study more detailed observables such as orientation-dependent and charge-state-correlated cross sections for a large class of complex targets ranging from biomolecules to atomic clusters.