We study the possibility of transferring population between two bound atomic or molecular states via an autoionizing state. Conditions for efficient transfer are given and the effects of the AC Stark shifts, the Fano parameters and the incoherent channels of ionization are explored. An adiabatic analytic solution which helps in the understanding of the behaviour of the system is also given. Efficient transfer is realized by using both a counterintuitive pulse sequence and concurrent laser pulses.
Population transfer between two valence states of the Li atom with a Raman process via intermediate autoionizing states well above the ionization threshold is investigated using a recently developed implementation of the muticonfiguration time-dependent Hartree Fock method. It is found that a properly chosen sequence of pump and Stokes $\ensuremath{\pi}$ pulses can yield a population transfer efficiency of
53 at relatively low intensities, while the extension of the stimulated Raman adiabatic passage (STIRAP) approach to the XUV in this case is far less efficient and loses its characteristic robustness at high intensities. A rule of thumb for when STIRAP is practical is given, suggesting that at still shorter wavelengths STIRAP may be possible.