The status of current theoretical methods does not allow one to fully describe realistic attosecond VIS/UV pump – XUV/X-ray probe experiments on the opto-electronic systems described in P2. The main problem is that, with the available tools, the connection of the theories to actual observables is rather indirect and still subject of controversy. In this project we will develop new theoretical tools that go beyond the state of the art to accurately represent ionization by XUV/X-ray attosecond probe pulses and the coupled electron and nuclear dynamics in medium-size and large molecules.