FAST ELASTIC E-H(2S) SCATTERING IN LASER FIELDS

A numerical method for the evaluation of the Born-Floquet amplitude fo r laser-assisted scattering is proposed for the case when a large basi s set is required to achieve convergence. The method is applied to ana lyze the elastic scattering of fast electrons by the H(2s) state in a low-intensity laser field of varying frequency and to study the resona nt scattering with increasing laser intensity. While the behavior of a n atom in a resonant field of low intensity is determined by virtual t ransitions between resonant levels, at high intensity a great number o f nonresonant virtual transitions may significantly influence laser-as sisted processes. As a consequence, the attenuation of resonant effect s could appear, as well as the ''local'' stabilization of the atom aga inst ionization. [S1050-2947(97)00411-3].