Adiabatic study of the positronium negative ion

The positronium negative ion is studied using an adiabatic treatment in hyperspherical coordinates. The potential curves of five different symmetries, ${}_{}{}^1{}_{}{}^{}\mathrm{S}_{}^{\mathrm{e}}{}_{}{}^{}$, ${}_{}{}^1{}_{}{}^{}\mathrm{P}_{}^{\mathrm{o}}{}_{}{}^{}$, ${}_{}{}^3{}_{}{}^{}\mathrm{P}_{}^{\mathrm{o}}{}_{}{}^{}$, ${}_{}{}^3{}_{}{}^{}\mathrm{P}_{}^{\mathrm{e}}{}_{}{}^{}$, and ${}_{}{}^1{}_{}{}^{}\mathrm{D}_{}^{\mathrm{e}}{}_{}{}^{}$, are discussed along with the corresponding resonant states. A new method for calculating the body-frame probability density is used to study the different symmetries and to distinguish between them.