The Lightest Three Body System : Positronium Negative Ion(Current Topics)

Abstract

The bound state of a positron and two electrons is known as positronium negative ion. Recently, we have observed efficient emission of the ions from alkali-metal coated tungsten surfaces. We have also succeeded in the observation of the photodetachment of the ions produced using this method. The experimental scheme developed in the present work gives new opportunities to study not only for the investigation of spectroscopic investigation for the ions but also for the production of an energy-tunable positronium beam for future applications.