The reactivity of methanimine radical cation (H$_2$CNH$^{+\cdot}$) and
  its isomer aminomethylene (HCNH$_2^{+\cdot}$) with C$_2$H$_4$
  Experimental and theoretical studies are presented on the reactivity of
methanimine and aminomethylene cations with ethene. Selective isomer generation
is performed via dissociative photoionization of suitable neutral precursors
and reactive cross sections and branching ratios are measured as a function of
photon and collision energies.
