LATTICE DYNAMICAL INVESTIGATION OF MÖSSBAUER RESONANCE STRENGTH AND THERMAL ENERGY SHIFT FOR 23.87 keV GAMMA-RAY OF Sn 119 IN IRON LATTICE

Abstract

Recently measured Mössbauer fraction and gamma-ray energy shift for 23.87 keV gamma-ray of Sn119 doped in iron lattice are analysed in the framework of Mannheim theory for impurity lattice dynamics and using the experimentally measured phonon frequency distribution function for the host lattice. The force constant change due to impurity, λ'/λ, which gives a good fit to the measured Mössbauer fraction turns out to be 0.4 in contrast to 1.0 reported by Price. By intercomparing the two above-mentioned measured quantities, an important parameter — absolute zero-point mean square velocity — related to the critical temperature of the superconductor is deduced. Zero-point kinetic energy of Sn119 in iron is also evaluated. Finally, by comparing these quantities with the corresponding quantities for Fe57 in iron, the effect of heavy impurity is studied