Photoabsorption and resonant photoemission in the region of Ne 1s double excitations

The absolute photoabsorption cross-sections of Ne in the regions 865-873 (1s Rydberg states) and 900-940 eV (double excitations) have been measured. Several new double excitation states were detected, including a very weak member of the series converging to the 1s2p53s conjugate shake-up ion state. States were also observed above the 1s2p5 double ionisation potentials, and are assigned to the 1s2snsnp series. At the first 1s2p53p2 double excitation state, the partial ionisation cross-section for the 1s-1 ion state resonates. The behaviour of the cross-section and Fano profile are analysed by a theoretical calculation using the time-independent scattering formalism.