Stability analysis of some periodic orbits in the hydrogen atom in parallel electric and magnetic fields

Abstract

The stability of some prominent periodic orbits in the hydrogen atom in parallel electric and magnetic fields is studied. For small field strengths, the application of classical perturbation theory allows for analytic treatments and provides useful information on possible types of classical motion and corresponding quantum states. Non-perturbative numerical and analytic stability analysis and calculations of the Liapunov exponent are performed for the straight-line orbit along the direction of the fields in the region of the zero-field ionization threshold. Bifurcation phenomena are discussed and related to recent photoexcitation experiments.