The stability of e+H-2

The recently discovered positronic molecule [J. Charry et al., Angew. Chem., Int. Ed. 57, 8859-8864 (2018)] has a new type of bond, the single-positron bond. We studied its stability using quantum Monte Carlo techniques. We computed an accurate potential energy curve of the reaction H− + PsH → → H2 + Ps− to establish its global stability with respect to all possible dissociation channels and to define the range of its local stability. We showed that the system is stable with respect to the dissociation into H− + PsH, with a binding energy of 23.5(1) mhartree. For R < 3.2 bohrs, the system is unstable, and it decays into H2 + Ps−. There are no other bound structures for R < 3.2 bohrs. We discuss possible routes to its experimental production.