Intermittent chaos in Hamiltonian systems: The three-dimensional hydrogen atom in magnetic fields

The trajectories of the highly excited hydrogen atom with nonvanishing pseudomomentum K are investigated. As a characteristic feature, we observe the intermittent behavior of the internal as well as of the center-of-mass motions which consist of alternating phases of strongly chaotic and quasiregular motion. During these phases, interesting physical phenomena appear. These phenomena as well as the intermittent behavior of the trajectories can be explained by the observation that, due to the finite nuclear mass, an additional confining potential appears. This confining potential has strong impact on the ionization of the hydrogen atom in general. We also investigate the correlation between the values of the internal angular momentum ${\mathit{L}}_{\mathit{z}}$ and the internal coordinate ρ. In fact, we are able to control intermittency by choosing different values of the energy, pseudomomentum, and magnetic-field strength.