Vicinage effects in the charge state of swift molecular constituents traversing thin foils

We present a method to calculate the charge state of the atomic ions resulting from the fragmentation of swift molecular ions when traversing thin foils. The mutual influence of the neighbouring ions in the charge state of each atomic ion and the asymmetries in the screening lose to the exit surface as each ion leaves the foil is taken into account. We have found the latter effect to be particularly important. Our calculations compare remarkably well with experimental data available for different molecular ions and foil thicknesses.