Rotational predissociation of HeH+: The effect of nuclear motion on ro-vibrational energies and widths

The approximate diagonal nuclear-motion correction for the X¹Σ⁺ state of HeH⁺ is calculated at selected points on the internuclear axis. The energies (E_υJ) and widthis (Γ_υJ) of the quasibound rotational-vibrational states of ⁴HeH⁺, ³HeH⁺, ⁴ HeD⁺ and ³HeD⁺ in the electronic ground state are calculated in the Born—Oppenheimer approximation using a discrete-states method. The E_υJ and Γ_υJ, corrected approximately for the effects of nuclear motion, are also evaluated.