Photodetachment cross sections of the positronium negative ion

Photodetachment cross sections of the positronium negative ion

The cross sections for the photodetachment from a weakly bound positronium negative ion Ps− below the threshold for the formation of Ps(n = 4) are calculated using the hyperspherical close-coupling method, and are compared with the corresponding spectra for the H− ion. Detailed resonance structures in the spectra near the Ps(n = 2, 3 and 4) thresholds are reported for the first time. The off-re...

Development of Energy-Tunable Positronium Beams Employing the Photodetachment of Positronium Negative Ions

Recent progress on the development of an energy-tunable positronium beam is reviewed. We describe experimental results for the efficient emission of positronium negative ions from alkali-metal coated tungsten surfaces. The ions generated using this technique have been accelerated by an electric field and photodetached in order to produce positronium beams with a hitherto unrealized energy range...

Observation of a shape resonance of the positronium negative ion.

When an electron binds to its anti-matter counterpart, the positron, it forms the exotic atom positronium (Ps). Ps can further bind to another electron to form the positronium negative ion, Ps(-) (e(-)e(+)e(-)). Since its constituents are solely point-like particles with the same mass, this system provides an excellent testing ground for the three-body problem in quantum mechanics. While theore...

Mass Spectra and Photodetachment of Sodium Fluoride Negative Ion Clusters

A flowing afterglow discharge ion source with NaF vaporized into the flow produces the expected stable anions F-(NaF),, as well as the unusual species Na(NaF); and (NaF); (n < 17). The dominance of (NaF); suggests that it has a particularly stable structure. A fixed-frequency laser has been used to photodetach electrons from mass-selected ion beams extracted from the flowing afterglow. Photoele...

Novel Doubly Excited States Produced in Negative Ion Photodetachment