INVESTIGATION OF ELECTRONIC-STRUCTURE AND ANISOTROPY OF THE LAMB-MOSSBAUER FACTOR IN ZNF2 SINGLE-CRYSTALS

Using the 93.3 keV resonance in Zn-67 the isomer shift, the quadrupole interaction, and the anisotropy of the Lamb-Mossbauer factor (LMF) in ZnF2 single crystals have been investigated. The main component of th e electric field gradient (efg) tenser V-22 = +(2.18 +/- 0.22) x 10(17 ) V/cm(2) and 77 = 0.29 +/- 0.03 are derived. V,, is oriented perpendi cular to the crystallographic c axis. The anisotropy of the LMF is lar ge: f(x) = (2.4 +/- O.1)%, f(y) = (2.3 +/- 0.2)%, and f(z) = (1.4 +/- 0.2)%. Ab initio Hartree-Fock cluster calculations gave a detailed des cription of the observed charge distribution including the orientation of the efg tenser. Using a force constant model (shell model), we sol ved the eigenvalue problem of the dynamic matrix and quantitatively re produced the anisotropy of the LMF.