MOSSBAUER STUDY OF SNO LATTICE-DYNAMICS

Lattice dynamics of tin monoxide was investigated by Mossbauer spectroscopy in the range 16-294 K. From the temperature dependence of the absolute recoil-free fraction, f(T), the second moment of the phonon spectrum and the anharmonic constant epsilon(-2) were determined. These results suggest that the dominant anharmonic contribution arises from the cubic term of the vibrational phonon-phonon coupling Hamiltonian. The absolute recoilless fraction was determined at room temperature by the linewidth method and found to be f(295 K) = 0.12(1). No phase transitions were observed in this temperature range. The Mossbauer-line intensity-ratio-data temperature dependence displays a likely vibrational anisotropy.