Mössbauer Spectroscopy

Abstract

Rudolf Mossbauer discovered in 1957 that gamma radiation can be emitted and absorbed by nuclei in solid matter without imparting recoil energy to the individual emitting nucleus and without Doppler broadening of the gamma line. At an early stage he gave a theory of the fraction of “recoilless” emission based on considerations of Lamb about clastic neutron scattering in solids.¹) In Chapter 6 a classical approach is used to derive formulas for the recoilless fraction of gamma emission, f(T), as a function of temperature. Here, only the general result is given:

$${\text{f}}({\text{T}}) = {{{\text{e}}}^{{{\text{ - }}{{{\text{k}}}^{{\text{2}}}}\left\langle {{{x}^{2}}} \right\rangle T}}}, $$

((1))

where k = 2π/λ is the wave number of the gamma ray and the <X²>_T component of the mean square vibration amplitude of the emitting (or absorbing) nucleus in the direction of the gamma ray. Eq. (1) is valid in the harmonic approximation of lattice vibrations.