Potential energy surface for the lowest quartet state of the rubidium trimer is constructed, making use of the many-body decomposition. Interaction energies are calculated using the coupled-clusters method and interpolated using the reciprocal-power reproducing kernel Hilbert space interpolation method.
Both the two-body and three-body nonadditive parts are extrapolated to exhibit the correct long-range behavior. Consequences for the low-energy scattering are briefly discussed.