Theoretical Calculation Explaining Negative Transferred Hyperfine Constants of theVKCenter

Abstract

A quantitative calculation has been performed showing that the explanation of negative transferred hyperfine constants (THC) at nuclei of ions surrounding the $V_K$ center is exchange polarization of the ligand cores by the unpaired ${\sigma }_u$ electron of the molecule-ion. The moment-perturbed method was utilized and is shown to be capable of general calculations of exchange polarization in the solid state. The calculated values of THC in LiF for the nearest-neighbor ${\mathrm{Li}}^{+}$ and ${\mathrm{F}}^{-}$ ions which lie on the nodal plane of the unpaired ${\mathrm{F}}_2^{-}$ molecular orbital are -5.03 and -6.60 MHz, respectively. These theoretical values compare favorably with the experimental results of Gazzinelli and Mieher.