Annihilation of Positrons from theH−e+Ground State

The problem of the binding of a positron to a negative hydrogen ion has been treated by the variational method with a four-parameter trial function. The best values of the parameters yield a binding energy of 0.228 ev against the most favored mode of dissociation into hydrogen plus positronium. Pair annihilation from the ground state of similar bound ${\mathrm{H}}^{-}{e}^{+}$ systems might be expected to contribute a principal component to the radiation from the annihilation of positrons in the alkali hydrides. The theory of positron annihilation has been suitably extended for application to the present problem. The above wave function yields a mean life against two-photon annihilation of about four times that for singlet positronium, the difference arising mainly out of spin considerations. The calculation of the angular correlation of the annihilation radiation indicates a narrower peak than has been obtained experimentally by others in LiH and NaH.