Debye-Waller smearing

By Fourier transforming the EXAFS oscillations, a radial structure function is obtained (2U). The peaks in the Fourier transform correspond to the different coordination shells and the position of these peaks gives the absorber-scatterer distances, but shifted to lower values due to the effect of the phase shift. The height of the peaks is related to the coordination number and to thermal (Debye-Waller smearing), as well as static disorder, and for systems, which contain only one kind of atoms at a given distance, the Fourier transform method may give reliable information on the local environment. However, for more accurate determinations of the coordination number N and the bond distance R, a more sophisticated curve-fitting analysis is required. 

Another important factor is the Debye-Waller factor e °. This accounts for thermal and static disorder effects concerning the movement/position of atoms around their equilibrium/averaged position. A point to stress is that the nature of this term is different to the counterpart term in XRD." Since vibrations increase with temperature, EXAFS spectra are usually acquired at low temperature (below 100 K) in order to maximise information. Spectra at different temperatures may, on the other hand, allow decouple thermal and static contributions to DW. The DW term smears the sharp interference pattern of the sinusoidal term and cuts off EXAFS at sufficiently... 

Debye-Waller factors [53] obtained from tiK scattering of X-rays or neutrons with dense polymers, ie, about 0.2-0.4 A at ambient conditions. Of course, the local elasticity of the polymer matrix may deviate somehow from the mean elasticity introduced by the isotroj homogeneous smearing factor and a refinement mi t be advisable to account for the spectrum of . 

This is essentially the Debye-Waller factor of the chain smearing out the tube. This asymptotic form was first derived by deGennes. For inter-... 

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