Role of consistency effects on the antishielding of nuclear quadrupole moments: Comparison between diagrammatic and differential-equation approaches for the ferric ion

A detailed comparison is carried out between consistency contributions to the nuclear quadrupole antishielding factor for the ${\mathrm{Fe}}^{+3\mathrm{}}$ ion obtained by the linked-cluster many-body perturbation procedure, as well as a procedure employing perturbed wave functions used in conventional differential-equation procedures for studying antishielding factors. The agreement between results by the two procedures is found to be good, indicating that the procedure using perturbed wave functions is a viable one for studying consistency effects, at least for positive ions.