Short-range potential model for multiphoton detachment of theH−ion

The ${\mathrm{H}}^{\mathrm{-}}$ ion is modeled by an effective one-electron potential specified by a regularized three-dimensional δ-function potential. With the help of quasienergy methods, the multiphoton-detachment rate of this model ion by a plane-wave field of arbitrary elliptical polarization can be expressed as a one-dimensional integral that has to be evaluated numerically. The results exhibit a pronounced dependence on the polarization of the laser: circular polarization yields a rate that depends smoothly on frequency and intensity with barely noticeable thresholds. In contrast, linear polarization generates marked thresholds as well as structure in between. All of the calculated thresholds closely obey the Wigner threshold law. There is good agreement with the available data where the ponderomotive energy is kept constant while the frequency varies.