On the Einstein model for EXAFS parallel and perpendicular mean-square relative displacements

The correlated Einstein model for EXAFS parallel and perpendicular mean-square relative displacements (MSRDs) is discussed. By means of dynamical simulations on different crystalline structures, the error owing to the Einstein-fit model on the EXAFS MSRDs is estimated as a function of the standard deviation of the density of vibrational states. This error should be taken into account to improve the accuracy of the MSRDs.