Basis set dependence of magnetic shielding constant calculated by the Hartree-Fock finite perturbation method

We investigate the basis set dependence and the gauge origin dependence in the calculations of Se and Cd nuclear magnetic shielding constants of several selenium and cadmium compounds. We improve the basis set systematically by adding the first-order higher angular momentum basis functions (FOBFs) to the conventional basis sets, as proposed previously, in the ab initio Hartee-Fock/finite perturbation method. The calculated results become almost independent on the employed basis sets when this improvement is done. Furthermore, it is shown that the mechanisms of the chemical shifts are basis-set independent. The dominances of the p-hole mechanism in the Se chemical shift and the p-electron mechanism in the Cd chemical shift are valid for all the basis set examined in this paper.