MP2/CBS atomic and molecular benchmarks for H through Ar

We extrapolate to the MP2/CBS limit with a sequence of optimized n-tuple-zeta augmented polarized basis sets (n=4, 5, 6, and 7) for the entire set of 72 atoms, positive and negative atomic ions, homonuclear diatomic molecules, and hydrides representing the first two rows of the Periodic Table. The second-order correlation energies agree with accurate (+/- 0.01 mE(h)) numerical values (He, Be, Ne, Mg, Ar, Zn+2, and Kr) to within +/- 0.1%. These MP2/CBS limits of the 72 species can now be used as benchmarks to calibrate more approximate calculations using smaller basis sets.