Many-body theory for the nuclear quadrupole antishielding factor of theFe+3ion

Abstract

The linked-cluster many-body perturbation theory is used to calculate the Sternheimer antishielding factor ${\gamma }_{\infty }$ for the ${\mathrm{Fe}}^{+3\mathrm{}}$ ion. The net result for ${\gamma }_{\infty }$ comes out as -9.03 and is composed of -8.69 and -0.34, respectively, for zero and higher orders in the electron-electron interaction. The zero-order result is in good agreement with earlier work and derives a major contribution close to 85% from the $3p\to p$ radial excitations. The first-order effect represents the role of self-consistency, while the second-order one includes, in addition, the influence of correlation. Reasons for the smallness of the consistency and correlation contributions will be discussed.