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

Abstract

We present a series of numerically tabulated atom-centered orbital (NAO) basis sets with valence-correlation consistency (VCC), termed NAO-VCC- n Z. Here the index ‘ n Z’ 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-pV n Z, 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- n Z, increasing the contribution of the s and p functions to achieve the valence-correlation consistency. NAO-VCC- n Z 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- n Z 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 Møller–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.