Theoretical Dynamics of Heavy Rydberg States in Rb$_2$

Rydberg states, characterized by long-range Coulomb interactions, are normally associated with states consisting of an electron and a positively charged atomic or molecular ion, but can also occur as vibrational states in ionic bonds between atoms. In such heavy Rydberg states, the light electron is replaced by a much heavier negative ion. Compared to normal vibrational states these have unusual properties, including extremely large internuclear distances, large dipole moments, and an infinity of states below the ion-pair dissociation limit. Ion-pair states are difficult to observe in experiments, but recently detailed spectra of heavy Rydberg states in H$_2$ and Cl$_2$ have been reported. We collaborate with the experimental groups of E.\ E.\ Eyler and P.\ Gould (UConn) to find heavy Rydberg states in Rb$_2$. Recent theoretical results are presented, and we discuss the potential application of Rb$_2$ heavy Rydberg states in cold matter physics.