Since the number of tin atoms in the sample is constant as the lithium content changes, such intensity variations can only be caused by changes in the fraction of Sn atoms undergoing recoil-free absorption.
A similar recoil occurs during absorption of radiation by a nucleus.
In this case, there is a strong probability that the recoil momentum during absorption and emission of the gamma photon is taken up by the whole solid (or more precisely by its entire lattice).
In 1957 Rudolf Mössbauer, in what has been called one of the "landmark experiments in twentieth-century physics", discovered the resonant and recoil-free emission and absorption of gamma rays by atoms in a solid metal sample containing only 191Ir.
It is made possible by fixing atomic nuclei in the lattice of solids so that energy is not lost in recoil during the emission and absorption of radiation.
The emission of the photon causes the first electron to recoil in space, while the absorption of the photon's energy and momentum causes a comparable deflection in the second electron's path.
Structure, optical properties and stress levels are evaluated by elastic recoil detection analysis (ERDA), IR absorption, UV/vis spectrometry, Raman spectroscopy.
Mössbauer effect, also called recoil-free gamma-ray resonance absorption, nuclear process permitting the resonance absorption of gamma rays.
The composition and microstructure of the Ti-aC coatings have been characterized in detail by combining the techniques of Rutherford backscattering spectrometry (RBS) and hydrogen elastic recoil detection (ERD), transmission electron microscopy (TEM), X-ray absorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy.
This then reduces the recoil energy to nearly zero and thus allows resonance absorption to occur even for gamma rays.
The stoichiometry and structure of the films were determined by Fourier-transform infrared spectroscopy, Rutherford backscattering spectrometry, electron recoil detection analysis, X-ray photoelectron spectroscopy and X-ray absorption near edge spectroscopy at the Si K edge.
