We found that using 6 points with a minimum screened cutoff of 17 Ryd (i.e. 17, 18, 19, 20, 21, 22 Ryd) in the extrapolation yielded RPA correlation energies close to the minimum possible MAE using any 6 neighboring screened cutoffs. This range of screened cutoffs is in close agreement to the values of the screened cutoffs used with PAW pseudopotentials because calculations using PAW pseudopotentials typically use a smaller planewave cutoff than the value of 60 Ryd used here, suggesting that descriptions of χ 0 could be relatively insensitive to pseudopotential choice. This set of screened cutoffs was used to calculate the RPA energies of the catalytic systems.