Coherent control for ultrafast photochemical reactions

Many photochemical processes involving the breaking and formation of chemic al bonds take place on a femtosecond time scale. By means of ultrafast lase r pulses it became possible to monitor these events in real time with a tem poral resolution in the sub-20 fs regime. Moving beyond the observation to the control of chemical reactions requires additional theoretical and exper imental effort. We illustrate with the aid of selected model systems the co ncepts and possibilities of "passive" and "active" control and their differ ences.