Upper and lower repulsive potentials of H-He and H-H. Top: short-range part of the repulsive potential curve 6 ²Σ⁺ state (black line) of the H-He molecule compared with the 6 state (blue dashed line) of the H-H. Bottom: short-range part of the potential curves of C ² Σ⁺ state (black line) of the H-He molecule compared with the h state (blue dashed line) of H-H. E_e and are the potential energies of the initial (n = 2) and final (n = 3) atomic states of the transitions.