  Photoelectron spectra and photoelectron angular distributions obtained in
photoionization reveal important information on e.g. charge transfer or hole
coherence in the parent ion. Here we show that optimal control of the
underlying quantum dynamics can be used to enhance desired features in the
photoelectron spectra and angular distributions. To this end, we combine
Krotov's method for optimal control theory with the time-dependent
configuration interaction singles formalism and a splitting approach to
calculate photoelectron spectra and angular distributions. The optimization
target can account for specific desired properties in the photoelectron angular
distribution alone, in the photoelectron spectrum, or in both. We demonstrate
the method for hydrogen and then apply it to argon under strong XUV radiation,
maximizing the difference of emission into the upper and lower hemispheres, in
order to realize directed electron emission in the XUV regime.
