Resonance-enhanced multiphoton ionization: Interference effects due to harmonic generation

A general theoretical model for the treatment of multiphoton ionization is presented. In this treatment, we have explicitly included coherent effects resulting from harmonic generation. The predictions of this model are in agreement with experimental observations that we present in this paper. In addition, the model is contrasted with much earlier theoretical treatments of multiphoton ionization and accounts for the anomalous multiphoton-ionization behavior reported by others in the literature.