Basis set limits of the second order Møller-Plesset correlation energies of water, methane, acetylene, ethylene, and benzene

We report second order Møller-Plesset (MP2) and MP2-F12 total energies on He, Ne, Ar, H2 O, C H4, C2 H2, C2 H4, and C6 H6, using the correlation consistent basis sets, aug-cc-pVXZ (X=D-7). Basis set extrapolation techniques are applied to the MP2 and MP2-F12/B methods. The performance of the methods is tested in the calculations of the atoms, He, Ne, and Ar. It is indicated that the two-point extrapolation of MP2-F12/B with the basis sets (X=5,6) is the most reliable. Similar accuracy is obtained using two-point extrapolated conventional MP2 with the basis sets (X=6,7). For the molecules investigated the valence MP2 correlation energy is estimated within 1 m Eh. © 2007 American Institute of Physics.