Autoionizing transitions in neon studied by low-energy electron impact

Measurements have been made of the energies of electrons ejected from autoionizing states of neon following excitation by low-energy electron impact. Singly and doubly excited states with energies in the range 43-46 eV were studied using a resolution and signal level which enabled previously unobserved structure to be detected. Ejected-electron spectra measured down to about 1.5 eV above the excitation threshold show a shift in energy of some of the structure as the excess energy above the excitation threshold is reduced. This is interpreted as a post-collision interaction between the ejected electron and the low-energy scattered electron.