Angular-momentum couplings in long-range Rb-2 Rydberg molecules

We study angular-momentum couplings in Rb-87(2) Rydberg molecules formed between a Rydberg and 5S(1/ 2) ground-state atom. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering of the Rydberg electron with the 5S(1/2) atom, along with the fine-structure coupling of the Rydberg atom and hyperfine-structure coupling of the 5S(1/2) atom. We discuss the effects of these couplings on the adiabatic molecular potentials. We obtain bound-state energies, lifetimes, and electric and magnetic dipole moments for the vibrational ground states of the Rb-87(nD + 5S(1/2)) molecules in all adiabatic potentials, with fine and hyperfine structure included. The hyperfine structure gives rise to mixed singlet-triplet potentials. We also study the effect of the hyperfine structure on the deep S-3-wave-and P-3-wave-dominated adiabatic molecular potentials, which support high-l Rb-87(2) Rydberg molecules.