About non-existence of the molecular ion $bf H_3^{++}$

It is shown that the molecular ion ${rm H}^{++}_3$ does not exist in a form of the equilateral triangle. To this end, a compact variational method is presented which is based on a linear superposition of six specially tailored trial functions containing non-linear parameters. Careful optimization of a total of fifteen parameters gives consistently lower variational results for the electronic energy than can be obtained with standard methods of quantum chemistry even with huge basis sets as large as mcc-pV7Z.