On the Chemical Reaction of Matter with Antimatter

• Published in: Chemphyschem Vol. 8; no. 8; pp. 1145 - 1150
• Main Authors: Lodi Rizzini, Evandro, Venturelli, Luca, Zurlo, Nicola
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 04-06-2007; WILEY‐VCH Verlag; Wiley
• Subjects: antimatter; antiprotons; Atomic and molecular collision processes and interactions; Atomic and molecular physics; Chemical reactions, energy disposal, and angular distribution, as studied by atomic and molecular beams; elementary reactions; Exact sciences and technology; ions; Physics; positron; Scattering of atoms, molecules and ions; ions positron; Antimatter; Reactive collision; Inorganic compounds; Positrons; Hydrogen Molecular ions; Diatomic molecules; antimatter antiprotons; Coulomb interaction; Positive ions; elementary reactions; Antiproton reactions
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.200700051

A chemical reaction between the building block antiatomic nucleus, the antiproton (p̄ or ${\bar H^ - }$ in chemical notation), and the hydrogen molecular ion (${H_2^ + }$) has been observed by the ATHENA collaboration at CERN. The charged pair interact via the long‐range Coulomb force in the environment of a Penning trap which is purpose‐built to observe antiproton interactions. The net result of the very low energy collision of the pair is the creation of an antiproton–proton bound state, known as protonium (Pn), together with the liberation of a hydrogen atom. The Pn is formed in a highly excited, metastable, state with a lifetime against annihilation of around 1 μs. Effects are observed related to the temperature of the ${H_2^ + }$ prior to the interaction, and this is discussed herein.
Active antimatter: A chemical reaction between the building block antiatomic nucleus, the antiproton and the hydrogen molecular ion has been observed by the authors in a large temperature range (15–8000 K). The net result is the creation of an antiproton‐proton bound state, known as protonium (Pn), together with the liberation of a hydrogen atom (see figure).