The HeH+ isotopologues in intense asymmetric waveforms

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The dynamics of molecular bonds and their control on the time scale of the electrons using tailored laser fields is one of the central topics in the Priority Program QUTIF. Previously, the hydrogen molecular ion H2+ served as a model and object of study for theory development in strong-field physics. Without doubt, this molecular bond is of fundamental importance, but it is a special case insofar as it is a perfectly symmetric and thus non-polar bond.The helium hydride ion HeH+ as the simplest polar molecule is of fundamental relevance as well, which is shown already by the fact that it is the first molecule formed in the universe after the big bang. The study of its dynamics is important because all other bonds lie between the extreme cases of H2+ and HeH+. A particularly attractive feature is the practical availability of four isotopologues with strongly varying mass ratio.On the other hand, helium hydride is stable only as an ion. Therefore, it can be studied only with the substantial effort of an ion-beam setup. To achieve sufficient event rates, a powerful laser with 100 kHz pulse repetition rate is used. The laser field is manipulated on the sub-cycle time scale by variation of the carrier-envelope phase or by using a phase-coherent two-color field, to study the phase-dependence of dissociation, single- and double ionization. The central goal of this project is direct control of these fragmentation channels relative to each other by manipulating the optical waveform.The experiments are accompanied by two complementary theory projects. Due to the many degrees of freedom of the molecule (vibration, rotation, two electrons), the theory is challenging as well. One of the theory projects is based directly on the time-dependent Schrödinger equation and aims at solving it as accurately as possible. The other theory project uses Monte-Carlo simulations for the calculation of classical trajectories.