Atom-Antiatom Interactions

Atom-antiatom rearrangement collisions in which the nucleus-antinucleus bound state is formed are important processes in atom-antiatom interactions. We give a general discussion of the atom-antiatom interatomic potential energy $V$ and calculate $V$ for H-$\overline{\mathrm{H}}$, $\overline{p}$-H, and $\overline{M}$-Ar where $\overline{M}$ means antimuonium (${\mu }^{-}{e}^{+}$ atom). We apply the semiclassical and optical-potential methods to determine cross sections for rearrangement collisions. At low energies these collisions are the dominant processes leading to particle-antiparticle annihilation.