Ionization rates and energy-angular distributions at the barrier-suppression ionization of complex atoms and atomic ions

Analytical expressions are obtained for energy and angular distributions of ejected electrons at the barrier-suppression ionization and tunneling ionization of complex atoms and atomic ions be strong low-frequency laser radiation. Both linear and circular polarizations of the radiation are considered. The barrier-suppression results reduce to the tunneling expressions of Ammosov-Delone-Krainov (ADK) approach in the limit of weak fields compared to the barrier-suppression fields. Theory is also generalized to the case of resonance tunneling in diatomic molecular ions.