Potential Energy Curves and Binding Energies of Heteronuclear Ultralong-Range Rydberg Molecules: Case Study of the Rb-Cs system

Ultralong-range Rydberg molecules (ULRMs) have attracted significant interest due to their unique formation mechanisms and distinctive properties. We theoretically investigate the formation and characteristics of heteronuclear ULRMs, focusing on Rb-Cs systems. We calculate the vibrational energy levels of nS heteronuclear ULRMs and extend our analysis to polyatomic systems, tracing the evolution of binding energies as the molecular configuration changes. Our theoretical results are presented in terms of potential energy curves and the associated vibrational spectra, providing insight into the formation dynamics of these systems. These results also provide a framework for experimental efforts in probing heteronuclear ULRMs, which serve as a sensitive platform for investigating the fundamental properties of Rydberg atoms and their interactions with ground-state atoms, while providing a benchmark for \textitab initio calculations.