Imaging of the umbrella motion and tunneling in the ammonia molecule by strong-field ionization

The geometry-dependent ionization behavior of the ammonia molecule is investigated. Different theoretical approaches for obtaining the ionization yield are compared, all of them showing a strong dependence of the ionization yield on the inversion coordinate at long wavelengths ($\ge$ 800 nm). It is shown how this effect can be exploited to create and probe nuclear wave packets in neutral ammonia using Lochfra{\ss}. Furthermore, imaging of a wave packet tunneling through the barrier of a double-well potential in real time is discussed.