Shielding polarizabilities calculated at the coupled-cluster singles and doubles level augmented by a perturbative treatment of triple excitations.

The nuclear magnetic shielding polarizabilities of N$_2$, F$_2$, CO, HF, HCl, HCN, HNC and C$_2$H$_2$ have been computed at the coupled-cluster singles and doubles (CCSD) level augmented by a perturbative treatment of triple excitations [CCSD(T)] using gauge-including atomic orbitals (GIAOs) and a mixed analytical-numerical approach based on the numerical differentiation of analytically evaluated shieldings. Extended basis sets have been employed to ensure results close to the basis set limit, and convergence of the electron-correlation treatment is investigated.