Description
An analytic representation of the three-body potential for the ground state of the molecular ion $H^{++}_3$ in equilateral triangle configuration is presented. This representation is based on an adequate description of the two-body potential energy curve $V(R)$ for the diatomic molecule $H^+_2$. The accurate representation of $V(R)$ for $H^+_2$ is achieved by matching short and long distances behavior via two-point Pad ́e approximation. In general, the approximation provides 3-4 significant digits correctly.
