Calculated polarization after Coulomb excitation in beam-foil interaction

The excitation of a hydrogen beam by the shielded Coulomb potentials of the ionic cores of an Aufoil is calculated in first Born approximation for a beam velocityv=1.4 a.u. Different formation depths of the final 2p term are considered and weighted with the survival probability. Stokes parameters for the emitted light are compared with He (n=3→ 2) transitions. It is demonstrated that the coherence of the excitation by neighbouring target cores tends to reduce the excitation amplitudes for the 2pm states withm≠0. Adsorbates are estimated to have a considerable effect on the polarization.