Table shows the optimized parameters, MAD, RMSD, and MaxAD for extrapolation of CCSD(T) correlation energy to the CBS limit. The trends for {D,T}are similar to the trends in HF extrapolation; we see that the results get better as one goes from aug to jul to jun basis sets. For the {T,Q} calculations, the jul basis sets match the results of aug basis sets, whereas jun performs slightly worse compared to the other two. The final column of Table shows the overall figure of demerit defined by eq 2. The values are comparable to those mentioned above from Xi et al. gives the most important results, the total energy extrapolation. Since the total energy is the sum of HF and CCSD(T) correlation energies, the trends are the same as the HF and CCSD(T) correlation energy extrapolation. For {T,Q} extrapolation, the jul and aug results are almost the same, and jun is lightly worse. For {D,T} extrapolation, jul is slightly better than aug, and jun is much better. Comparing the results in Table and It is interesting to also look at the separate results for cations, neutrals, and anions.