The Mean-square Relative Displacement of Iron in Anharmonic XAFS Theory

Mean-square relative displacement (MSRD) of Iron (Fe) has been investigated in the anharmonic X-ray absorption fine structure (XAFS) theory. The thermodynamic parameters are derived from the influence of the absorbing and backscattering atoms of all their nearest neighbors in the crystal lattice with thermal vibrations. The MSRD is calculated in explicit forms using the classical anharmonic correlated Einstein model. The numerical results of Fe in the temperature range from 0 to 600 K are in good agreement with those obtained by the other theoretical models and an experiment at several temperatures. The analytical results show that the present model is useful in analyzing the experimental XAFS data of Fe.