Electric hyperfine interaction in199Hg fluorides

With the current integration technique, the Mossbauer effect on the 158 keV, 5/2−→1/2− transition in199Hg was studied using the cubic HgF2 and the tetragonal Hg2F2 as absorbers; in the latter, a quadrupole splittingeQVzz=}- 9.0(2) mm/s was observed. Electron densities were calculated with the self-consistent-charge-extended-Hueckel-molecular-orbital method and δ〈r2〉=(3.26±0.11) fm2 derived. From the quadrupole splitting and the calculation, an effective antishielding factor almost twice that of the neutral Hg atom is derived.