Fig. 9: Potential energy landscape of a Rydberg quasi-molecular complex.
The molecular PECs split into two branches, which belong to the \({}^{2}{{{\Sigma }}}_{\,\text{g}\,}^{+}\) and \({}^{2}{{{\Sigma }}}_{\,\text{u}\,}^{+}\) components of the quasi-molecular ion. The highest-lying PEC of each branch belongs to Ug(R) (Uu(R)) of the molecular ion. All other PECs \({U}_{\,\text{g,u}\,}^{(n,l)}(R)\) are shifted by the binding energy of the Rydberg electron. For simplicity, we restrict the plot to hydrogenic manifolds only. The multicolored PECs are relevant for the description of the state-changing collision process when starting with 20P-ULRMs (see also Fig. 4). When the frequency of the oscillating dipole ω = Δ(R) exceeds the binding energy of the Rydberg electron, the complex may undergo associative ionization. The gray dashed line indicates the energy limit as defined by the asymptotic potential of the initial state Ψi.
