A polarisation correlation study of the excitation of the H2d3Πu(ν1=0, N1=1) level by electron impact

Abstract
Full details are given of an experiment in which the three normalised Stokes' parameters characterising the decay of the electron impact excited d 3 Pi u (v1=0, N1=1) rotational level of H2 were determined in an electron-photon coincidence experiment at 25 eV impact energy and over the angular range 20-60 degrees . An analysis shows how these parameters are related to the state multipoles characterising the excited state. The rather low degree of coherence which was observed is consistent with various depolarising effects, namely the averaging over magnetic sublevels which occurred in both the excitation and decay channels and also the perturbations due to fine and hyperfine structure relaxations.