Energies above D$_{as}$ Binding energies J,Ω,j, v$_{t}$ , v$_{d}$ ,Γ Present study Calculations of [10] Present study Calculations of [10] 0,0,0,0,0, A ′ 1 2103.3 2100.6 -70.7 -68.4 0,0,0,1,0, A ′ 1 2148.4 2147.1 -25.6 -21.9 0,0,0,2,0, A ′ 1 2168.7 2165.9 -5.4 -3.1 0,0,0,3,0, A ′ 1 2174.1 2168.7 -0.01 -0.3 D$_{00}$ a ) 2174.1 2169.0 0,0,1,0,0, A ′ 2 2140.3 2140.8 -152.1 (-33.7) n/a (-28.2) 0,0,1,1,0, A ′ 2 2215.1 -77.4 0,0,1,2,0, A ′ 2 2259.3 -33.2 0,0,1,3,0, A ′ 2 2281.9 -10.6 0,0,1,4,0, A ′ 2 2290.9 -1.6 D$_{01}$ b ) 2292.5 n/a a ) Asymptotic energy of H − +H$_{2}$( v d = 0 ,j = 0) dissociation b ) Asymptotic energy of H − +H$_{2}$( v d = 0 ,j = 1) dissociation TABLE II: Comparison of energies (in cm − $^{1}$) of H − 3 bound levels obtained in the present study with those of Ref. [10]. Energies in the second and third columns are given with respect to D$_{as}$ (see Table I). The binding energies (fourth and fifth columns) are given with respect to the dissociation limits D$_{00}$ (for A ′ 1 levels) and D$_{01}$ (for A ′ 2 levels). The energies in parentheses are given with respect to D$_{00}$ , to compare with Ref.[10]. V. PERMANENT DIPOLE MOMENT SURFACE FOR THE H − 3 GROUND STATE. The Molpro package delivers also the components of the permanent dipole moment to- gether with the PES. For a fixed geometry, the obtained components of the dipole moment correspond to the coordinate system with the X, Y, Z axes along the principal axes of inertia of the molecule. In our notations, the Y -axis is orthogonal to the plane of H − 3 , therefore D$_{Y}$ = 0. For γ = 0 and 90 ° there is only one non-zero component ( D$_{Z}$ in our notations). D$_{Z}$ becomes also equal to zero at equilateral geometries. For other geometries ( γ =0 or 90 ° ) there are two non-zero components, D$_{Z}$ and D$_{X}$ . We used the following convention to 18