Correlation between Mössbauer Resonance Strength and Second-Order Doppler Shift: Estimate of Zero-Point Velocity

Mössbauer results on the absolute resonance strength $\ln f$ and on the second-order Doppler shift are found to be approximately linearly related to each other for a variety of systems. This parametric representation of the experimental results (with temperature as a parameter) permits the deduction of the zero-point mean-square velocity of the resonant impurity nuclei. Data from a number of sources are presented, and various derived quantities are tabulated. The correlation is shown also to hold for two highly anharmonic cases. An experimental test of the Kagan relation between $\ln f$ at $T=0\mathrm{}$ and the shift is given.