Short-time behavior in multiphoton ionization

Abstract

The short-time behavior of atomic multiphoton-ionization profiles is investigated using simplified models of the field and the atom. The importance of including many levels in the model atom, of spontaneous emission, and of pulse shape are studied in detail. It is shown that the first two of these have little influence on the qualitative behavior of the short-time behavior of the resonance profile, but that the third, the pulse shape, is critical in determining the time evolution of the resonance profile.