Strong field atomic ionization: Origin of high-energy structures in photoelectron spectra
|Strong field atomic ionization: Origin of high-energy structures in photoelectron spectra
|Year of Publication
|Wassaf, J, Veniard, V, Taieb, R, Maquet, A
|PHYSICAL REVIEW LETTERS
Two distinct interpretations have been proposed to account for conspicuous enhancements of the ionization peaks in the high energy part of above-threshold ionization spectra. One of them ascribes the enhancement to a multiphoton resonance involving an excited state, while other analysis performed for zero-range model potential link it to ``channel closings, `` i.e., to the change in the number of photons needed to ionize the atom when the laser intensity increases. We report the results of model calculations that confirm the existence of a resonant process in atoms and shed light on why short-range potential models can mimic the experimental observations.