Laser Probing of Metastable Atoms and Molecules Deflected by Electron Impact

A new technique for determining electron impact metastable excitation cross sections which exploits angular deflection of the target is presented. The deflected targets, further excited by laser radiation which is resonant between the metastable state and a high- $n$ Rydberg state, are detected using field ionization. The target deflection angle and flight time determines the associated electron scattering angle, whereas the laser probes individual states of the electron excited manifold. New information over a full range of scattering angles from forward to backward scattering is then obtained.