Photodetachment of H- ion in a nonuniform electric field

The photodetachment of H- ions in a nonuniform electric field has been investigated on the basis of closed orbit theory. Firstly, we give a clear physical description of the detached electron's movement in a nonuniform electric field. Then we put forward an analytical formula for calculating the photodetachment cross section of this system. Our study suggests besides the closed orbit previously reported for the photodetachment of H- in a uniform electric field, some additional closed orbits are produced owing to the effect of the nonuniform electric field. Compared with the photodetachment cross section of H- in a uniform electric field, the oscillation in the cross section of our system becomes much more complicated and the cross section exhibits a multiperiodic oscillatory structure. To show the relation between the oscillation in the photodetachment cross section and the detached electron's classical closed orbits clearly, we make a Fourier transformation for the scaled photodetachment cross section of this system. Each peak in the Fourier transformed cross section corresponds to the contribution of one closed orbit. This study provides a new understanding of the photodetachment of negative ions in the presence of a nonuniform electric field. (author)