Influence of an added parallel electric field on diamagnetic hydrogen oscillator strength spectra

We present oscillator strength spectra of the hydrogen atom in parallel magnetic and electric fields obtained via the pseudospectral method, a two-dimensional spatial discretization scheme. We have observed that for the field strength regimes of interest (gammaless than or equal to0.2 a.u. and Fless than or equal to10(8) V/m), a simple perturbation theory analysis accurately accounts for the electric-field effect on most transitions in the Balmer alpha series. Nearly constant oscillator strengths for some transitions at given field strengths observed by Fassbinder and Schweizer [Astron. Astrophys. 314, 700 (1996)] are explained theoretically. An effective strategy in using the pseudospectal method has also been suggested for handling the hydrogen atom in crossed magnetic and electric fields.