LATTICE-DYNAMICS AND HYPERFINE INTERACTIONS OF THE INTERCALATION COMPOUNDS - NBS2.SN AND NBS2.SN1/3

The vibrational anisotropy of tin in the two intercalation compounds NbS2·Sn 1 3 and NbS2·Sn has been studied over the temperature range 78 ≤ T ≤ 320 and 4.2 ≤ T ≤ 320°K, respectively, using 119Sn 23.4 Kev gamma resonance spectroscopy. As in the case of the Tantalum homologue, NbS2·Sn 1 3 shows a single resonance maximum indicating a cubic symmetry charge distribution around Sn. The effective Mossbauer (lattice) temperature is 197 ± 5°K. The gamma resonance spectrum of NbS2·Sn shows a doublet with a quadrupole hyperfine interaction of 0.954 mm sec-1 at 78°K. The intensity ratio of this doublet is temperature dependent and has been analyzed in terms of the Golldanskii-Karyagin Effect to yield a value for 〈x2|〉 - 〈x2⊥〉 = -1.3 × 1018 cm2 at 3000°K. The effective Mössbauer (lattice) temperature for the 1 : 1 compound is 159 ± 5°K calculated from the high temperature limiting slope of the recoil-free fraction temperature dependence. The origin of the isomer shift differences between the TaS2 and NbS2 intercalation compounds of tin is discussed. © 1979.