Recoilless fraction on 197Au Mössbauer spectroscopy

The recoilless fraction is a parameter that reflects lattice vibrations and provides important knowledge in physics, chemistry, etc. However, in the commonly used 57Fe Mössbauer spectroscopy, the recoilless fraction is not actively measured. This is because the recoil energy of 57Fe is low, and the recoilless fraction is usually saturated at low temperature to room temperature. On the other hand, in 197Au Mössbauer spectroscopy, the energy of γ-rays is high, so differences and changes in the recoilless fraction appear significantly. We attempted to estimate the Debye temperature not from the absolute amount of spectral absorption area but from its temperature dependence curve. The Debye temperature was estimated by fitting the temperature dependence curve with the calculated value of the Debye model. We estimated the Debye temperature of metallic Au with reasonable accuracy to the literature value and estimated that of Au compounds. Also, we estimated almost the same Debye temperature for samples with different thicknesses. Although this method is simple, it is helpful for 197Au Mössbauer spectroscopy.