  We demonstrate how the shape of femtosecond laser pulses can be tailored in
order to obtain maximal ionization of atoms or molecules. For that purpose, we
have overlayed a direct-optimization scheme on top of a fully unconstrained
computation of the three-dimensional time-dependent Schrodinger equation. The
procedure looks for pulses that maintain the same total length and integrated
intensity or fluence as a given pulse that serves as an initial guess. It
allows, however, for changes in frequencies -- within a certain, predefined
range -- and overall shape, leading to enhanced ionization. We illustrate the
scheme by calculating ionization yields for the H2+ molecule when irradiated
with short (~5 fs), high-intensity laser pulses.
