Observed photodetachment in parallel electric and magnetic fields

Abstract

We investigate photodetachment from negative ions in a homogeneous 1.0-T magnetic field and a parallel ac electric field of $\ensuremath{\sim}10\mathrm{V}/\mathrm{c}\mathrm{m}.$ A theoretical model for detachment in combined fields is presented. Calculations show that a field of 10 V/cm or more should considerably diminish the Landau structure in the detachment cross section. The ions are produced and stored in a Penning ion trap and illuminated by a single-mode dye laser. We present preliminary results for detachment from ${\mathrm{S}}^{\ensuremath{-}}$ showing qualitative agreement with the model. Future directions of the work are also discussed.