THE PHOTOELECTRON ENERGY-SPECTRA OF THE ABOVE-THRESHOLD IONIZATION OF ATOMIC-HYDROGEN

The above-threshold photoelectron energy spectra of the hydrogen atom in an intense field are calculated by solving the Schrodinger equation in momentum space, which facilitates the extraction of the rapidly varying part of the wavefunction. It is found that the peak switching and the suppression of low-energy peaks in the above-threshold ionization is clearly manifested in this theory. We found that the apparent threshold shifts of the ATI peaks are strongly dependent on the final continuum state. The frequency dependence of the energy spectrum is also investigated.