  Experimental charge exchange and energy loss data for the transmission of
slow highly charged Xe ions through ultra-thin polymeric carbon membranes are
presented. Surprisingly, two distinct exit charge state distributions
accompanied by charge exchange dependent energy losses are observed. The energy
loss for ions exhibiting large charge loss shows a quadratic dependency on the
incident charge state indicating that equilibrium stopping force values do not
apply in this case. Additional angle resolved transmission measurements point
on a significant contribution of elastic energy loss. The observations show
that regimes of different impact parameters can be separated and thus a
particle's energy deposition in an ultra-thin solid target may not be described
in terms of an averaged energy loss per unit length.
