Effect of initial-state orbitals on the angular correlation pattern in double photoionization

The neon 2p4 1Se triple differential cross section (TDCS) of photoionization has been measured under equal energy sharing and displays two additional lobes compared with the related TDCS of helium. A model for the TDCS is derived which parameterizes the relative magnitudes and phases for the epsilon S epsilon p and epsilon p epsilon d continuum channels in addition to an electron correlation factor and reproduces the experimental data very well. This model traces the appearance of these additional lobes to the existence and interference of two continuum channels in the final state wavefunction. The present measurement serves as a test case for the more complicated treatment of energy- and angle-resolved double photoionization in rare gases other than helium,.