ELECTRON ANGULAR-DISTRIBUTIONS AFTER ABOVE-THRESHOLD MULTIPHOTON DETACHMENT OF H- BY 1064 NM RADIATION

We present a non-perturbative Floquet calculation of the electron angu lar distributions and partial widths for multiphoton above-threshold d etachment of H- by 1064 nm radiation. When a beam of H- ions is used a s a target, the angular distributions in the frame where the ions are at rest can be extracted from the energy (angle-integrated) distributi ons in the laboratory frame. The experiments measuring the electron an gular distributions are now in progress. Our calculation procedure con sists of the following elements. (i) Determination of the resonance wa vefunction and complex quasienergy by means of the non-Hermitian Floqu et Hamiltonian formalism. The Floquet Hamiltonian is discretized by th e complex-scaling generalized pseudospectral technique recently develo ped (by Wang and co-workers). (ii) Calculation of the angular distribu tion and partial widths based on an exact integral formula. The calcul ations were performed for the linearly polarized laser field with the wavelength 1064 nm and several intensities in the range 10(9)-10(12) W cm(-2). With the increase of the number of photons absorbed above the threshold, the angular distributions become more stretched along the field direction manifesting, however, a few additional maxima. Besides the numerical data for the angular distributions we also present the coefficients of expansion on the basis of Legendre polynomials.