Single-photon multiple ionization of neon in the K-edge region

The ion charge state yields resulting from the photoionization of neon gas have been measured with time-of-flight ion charge state spectroscopy for excitation energies in the K-edge region. The decay of the [1s]3p resonance excited state results in the formation ion charge states Ne+, Ne2+, Ne3+, and Ne4+, with a branching ratio of 0.65:0.32:0.030:0.002, whereas the final charge state for the decay of higher-order [1s]np(n greater than or equal to 4) and [1s]epsilon p continuum excitations is mostly Ne2+. We have measured (q) over bar, the mean charge from photoionization, for excited states near the K edge as a function of photon energy. Postcollision interaction effects are shown to be quite small.