  We construct a reference benchmark set for atomic and molecular
random-phase-approximation (RPA) correlation energies in a density functional
theory (DFT) framework at the complete basis set limit. This set is used to
evaluate the accuracy of some popular extrapolation schemes for RPA
all-electron molecular calculations. The results indicate that for absolute
energies accurate results, clearly outperforming raw data, are achievable with
two-point extrapolation schemes based on quintuple- and sextuple-zeta basis
sets. Moreover, we show that results in good agreement with the benchmark can
also be also obtained by using a semiempirical extrapolation procedure based on
quadruple- and quintuple-zeta basis sets. Finally, we analyze the performance
of different extrapolation schemes for atomization energies.
