Quadrupole interactions studies of Hg in Zn and lattice location of Hg and Au in Zn

197Hg, 199Tl and 199Au ions were implanted into Zn single crystals. From time differential perturbed e--γ and β-γ angular correlation experiments with the 5/2- states in 197Hg and 199Hg, respectively, the quadrupole interaction for Hg in Zn is reinvestigated. Only the data for the 199Au sample exhibit a single unique quadrupole precession pattern in agreement with the result of the lattice location studies by use of the channeling technique, which show Hg to occupy random lattice sites in Zn while Au is substitutional. From the measured interaction frequency, sign and magnitude of the effective electric field gradient for Hg on the substitutional site in Zn is determined as Vsup(eff)sub(zz) = +15.2(1.8) x 1017V x cm-2. By comparison of this value to the corresponding lattice field gradient contribution an electronic enhancement factor of K(HgZn) = 2.6 is deduced in disagreement with a previous derivation of this quantity, but which supports the proposal that the electronic field gradient depends linearly upon the valence of the impurity probe atom. (orig.)