Long-range states and Feshbach resonances in collisions between ultracold alkali-metal diatomic molecules and atoms

We consider the long-range states expected for complexes formed from an alkali-metal diatomic molecule in a singlet state and atom. explore structure of Hamiltonian such systems, couplings between six angular momenta that are present. patterns densities states, terms can cause Feshbach resonances when cross threshold as function magnetic field. present case study $^{40}\mathrm{K}^{87}\mathrm{Rb}+^{87}\mathrm{Rb}$. show multiple types resonance due to with rotational and/or hyperfine excitation, likelihood them existing at low moderate fields.