CONICET | Buscador de Institutos y Recursos Humanos

Above-threshold ionization of atoms by XUV short laser pulses with frequenciesclose to the resonant 1s-2p transition is investigated. We present a theory based on a variationalexpression using trial wave functions for the final and the initial states. For the former weuse a Coulomb-Volkov wave function, and for the latter a close-coupling solution of the timedependent Schr¨odinger equation considering a few bound states. The close-coupling Coulomb-Volkov theory, fully accounting for the important 1s-2p transition, explains the photoelectronspectrum as well the total ionization cross sections for the resonant case. We also comparethe partial wave populations and angular distributions given by the theory with the numericalsolutions of the time-dependent Schr¨odinger equation.