A field ionizer for photodetachment studies of negative ions

• In this paper, we present an apparatus for studies into the photodetachment process of atomic negative ions. State-selective detection of the residual atom following the initial photodetachment step is achieved by combining resonant laser excitation of the photo-detached atom with electric field ionization. The resonance ionization technique in combination with a co-linear ion–laser beam geometry gives an experimental apparatus that has both high selectivity and sensitivity. In addition to measurements of a single selected partial photodetachment channel, the apparatus also can be used to study a manifold of photodetachment channels in which the residual atom is left in a high-lying Rydberg state and for investigation of the double electron-detachment process. Ion-optical simulations in SIMION are used to illustrate the operation of the apparatus for studying such processes. Successful performance of the apparatus against the simulation is demonstrated by a high resolution study of the photodetachment of cesium, where the sharp s-wave threshold of the photodetachment processes leaving the residual atom in the excited 6p state was investigated.

Subject headings

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

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ref (subject category)

art (subject category)