Resonances in the double-ionization signal of two-electron model atoms

Using numerical simulations, we examine the wave-function probability density of a model two-electron atom exposed to intense femtosecond laser pulses. We determine numerically the lowest-lying energies and eigenstates of the model atom. This information is then used to identify resonance features within the double-ionization yield, defined as probability density in which both electrons are far from the nucleus, and the atomic levels responsible for these features. This resonance behavior is confirmed using two distinct procedures.