Calculation of electric dipole hypershieldings at the nuclei in diatomic molecules

The third-rank electric hypershielding at the nuclei of eight diatomic molecules and carbon dioxide has been evaluated at the Hartree-Fock level of accuracy (i) by straightforward use of its definition within the Rayleigh-Schrodinger perturbation theory and (ii) by a pointwise procedure for geometrical derivatives of electric dipole polarizability. The connection between these quantities is provided by the Hellmann-Feymnan theorem. Extended ad hoc basis sets of big size and high flexibility have been employed in a numerical test of the theory to assess its practicality. It is shown that constraints for rototranslational invariance and conditions provided by the virial theorem yield a natural criterion for near Hartree-Fock quality of nuclear electric hypershieldings computed by procedure (i). (C) 2002 Elsevier Science B.V. All rights reserved.