Strong-field controlled fragmentation of polyatomic molecules

Control over the instantaneous electric field via e.g. the carrier-envelope phase (CEP) allows to directly access the complex electronic and subsequent nuclear dynamics of molecules. In the first part of this talk, the results of theoretical modeling for recent experimental measurements, demonstrating efficient control over fragmentation of polyatomic molecules via CEP tuning in the laser pulse, will be present. Control can be achieved in the regime of predominantly non-sequential double ionization, where the first electron after liberation may return to the parent ion and upon re-collision ionizes a second valence electron. The mechanism of control is based on fine tuning of electron impact energy of, resulting in selective ionization of the outermost or an inner valence electron. Ionization of the outermost electron leads to formation of a stable doubly charged molecular cation, whereas removal of an inner valence electron causes inevitably molecular fragmentation.
In the second part of the talk, I will present very new experimental and theoretical data extending the approach towards achieving additionally channel-selective fragmentation, utilizing the alignment of the molecule relative to the polarization axis of the laser as an additional control tool. Here, control is introduced in the ionization step, as different molecular orbitals feature alignment-dependent contributions to the ionization.