Ivanov, IgorKheifets, Anatoli2015-12-070969-806Xhttp://hdl.handle.net/1885/17666Laser light intensities, currently obtained in the laboratories, make it possible to observe many multi-photon phenomena in the interaction of light and matter (such as multi-photon ionisation or MPI process). Theoretical description of such phenomena necessitates the use of essentially non-perturbative framework. We present such an approach based on the recasting of the Schrodinger equation for the system atom+field into a set of coupled integral equations of the Lippmann-Schwinger type.Keywords: High intensity light; Hydrogen; Integral equations; Laser beams; Multiphoton processes; Perturbation techniques; Photoionization; Kramers-Henneberger Hamiltonian; Multi-photon ionization (MPI); Non-perturbative phenomena; Strong laser fields; Inert gases; Kramers-Henneberger Hamiltonian; Multi-photon ionisation; Non-perturbative phenomena; Strong laser fields200610.1016/j.radphyschem.2005.07.0662015-12-07