Numeric atom-centered-orbital basis sets with valence-correlation consistency from H to Ar

We present a series of numerically tabulated atom-centered orbital (NAO) basis sets with valence-correlation consistency (VCC), termed NAO-VCC-nZ. Here the index 'nZ' refers to the number of basis functions used for the valence shell with n = 2, 3, 4, 5. These basis sets are constructed analogous to Dunning's cc-pVnZ, but utilize the more flexible shape of NAOs. Moreover, an additional group of (sp) basis functions, called enhanced minimal basis, is established in NAO-VCC-nZ, increasing the contribution of the s and p functions to achieve the valence-correlation consistency. NAO-VCC-nZ basis sets are generated by minimizing frozen-core random-phase approximation (RPA) total energies of individual atoms from H to Ar. We demonstrate that NAO-VCC-nZ basis sets are suitable for converging electronic total-energy calculations based on valence-only (frozen-core) correlation methods which contain explicit sums over unoccupied states (e.g. the RPA or second-order Moller-Plesset perturbation theory). The basis set incompleteness error, including the basis set superposition error, can be gradually reduced with the increase of the index 'n', and can be removed using two-point extrapolation schemes.