Scaled-energy spectra and closed classical orbits of the hydrogen atom in parallel electric and magnetic fields.

Abstract

Rydberg atoms in strong fields have scaling properties that allow detailed interpretation of photoabsorption spectra in terms of classical trajectories. The classical dynamics remains invariant if a spectrum is obtained at constant scaled energy. Since each orbit which is closed at the nucleus produces a sinusoidal modulation in the absorption spectrum, its signature is a peak in the Fourier transform of a scaled-energy spectrum. This paper identifies the effect of closed orbits in the computed spectrum of the hydrogen atom in parallel electric and magnetic fields in a region where chaos is just beginning to develop.