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Updated: Sep 26, 2026

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Double photoexcitation of helium in a strong dc electric field
James R Harries1, James P Sullivan, James B Sternberg
1Photon Factory, IMSS, KEK, 1-1 Oho, Tsukuba-shi, Ibaraki-ken, 305-0801 Japan.
Abstract:
We report the first experimental measurements of the effect of an applied field on the photoexcitation and autoionization of doubly excited states of helium. Ground-state photoionization spectra have been measured in the region below the He+(N=2) threshold with static electric fields of up to 84.4 kV/cm across the interaction region. The results are compared to the theoretical calculations of Chung et al. [J. Phys. B 34, 165 (2001)]], which are the only calculations available in this regime. Transitions to several states in the N=2, n=6 manifold are assigned, and a wealth of new structure is observed. Our data show that many more series are mixed in by the field than those predicted by theory.
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