Exotic ultralong-range Rydberg molecules

The discovery of Rydberg matter empowers prospects in ultracold science. Recently, scientists took another step forward by measuring the Rydberg series of highly magnetic lanthanide – Er. We intend to examine the complex entity of the ultralong-range Rydberg molecule and search for intriguing energy structure, novel transitions, and unusual magnetic properties. In our work, we first describe Er with Multichannel QuantumDefect Theory to calculate the energy spectrum of the Rydberg molecule composed of excited Er and groundstate Rb. We use the perturbation theory due to insufficient experimental data for a general model. A step towards developing a proper model is understanding molecules with a two-valence electron Rydberg atom. Here, the Hg*Rb molecule serves as a platform. We present promising energy spectra with easily accessible states and approach homonuclear Hg molecule calculations.