Abstract. We present a non-perturbative Floquet calculation of the electron angular distributions and partial widths for multiphoton above-threshold detachment of by 1064 nm radiation. When a beam of ions is used as a target, the angular distributions in the frame where the ions are at rest can be extracted from the energy (angle-integrated) distributions in the laboratory frame. The experiments measuring the electron angular distributions are now in progress. Our calculation procedure consists of the following elements. (i) Determination of the resonance wavefunction and complex quasienergy by means of the non-Hermitian Floquet Hamiltonian formalism. The Floquet Hamiltonian is discretized by the complex-scaling generalized pseudospectral technique recently developed (by Wang and co-workers). (ii) Calculation of the angular distribution and partial widths based on an exact integral formula. The calculations were performed for the linearly polarized laser field with the wavelength 1064 nm and several intensities in the range - . 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.

Print publication: Issue 19 (14 October 1996)
Received 20 May 1996