Calculation of state selective field ionization of hydrogen atoms in a strong magnetic field

We have performed classical and quantum calculations for a hydrogen atom in a strong magnetic field exposed to a parallel electric field that linearly increases with time. The calculations were performed for the situation where the electron is launched from near the nucleus and for a microcanonical ensemble. For the case of low angular momentum, the classical and quantum calculations are compared. We show that there exist stable classical trajectories at positive energy and that these contribute to the possibility of the atom surviving to strong electric fields. The dependence of the survival probability versus electric field strength can be used to estimate the behaviour of Rydberg anti-hydrogen atoms in the ALPHA and ATRAP experiments.