Measurements of photoelectron angular distributions for rotationally resolved transitions in para-H 2 +

Rotationally resolved measurements of photoelectron angular distributions for the X2?g+(v+=0, N+=0) ground state of para-H2+ are presented, over the photon energy range, 15.47 to 15.75 eV, that includes most of the dominant autoionising resonances decaying into the ground ionic state. It is observed that the value of the asymmetry parameter in this energy interval is close to 2, but sharp variations are observed at particular photon energies. The measurements were performed using synchrotron radiation, a high-resolution hemispherical analyser and a magnetic angle changer.