The effects of a finite scattering volume on the determination of electron impact coherence parameters

In this paper, we specifically examine the consequences of a finite scattering geometry on ''in-plane'' coherence experiments, i.e. polarization correlation or superelastic scattering experiments in which the incidence vector of the detected photon or the laser 'photon lies in the nominal scattering plane (φν = 0). The ''in-plane'' experimental configuration is adopted in order to give direct information about spin-orbit coupling effects. We show that a finite scattering geometry can give rise to severe distortion in the dependence of the coincidence or superelastic scattering signal intensity on the photon polarization and that this distorted behavior can be misinterpreted as arising from spin-orbit coupling effects. 11 refs., 3 figs