Effect of the electron mean free path in small particles on the extended

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Abstract
The transferability of the electron mean-free-path (MFP) value from the bulk standard to small particles is a standard procedure in the analysis of extended x-ray-absorption fine-structure (EXAFS) measurements. In this paper we show, using a simple example, that transferability of the MFP can lead to an incorrect evaluation of the coordination number. The electron MFP in small particles can be significantly different from the bulk. We illustrate this point by evaluating the electron MFP of Al small particles. We discuss examples where assuming transferability of the electron MFP can cause erroneous conclusions concerning the dispersion and shape of small clusters of atoms. The error in the coordination number can be very large for small particles. The effect of particle size on the MFP is strongly dependent on the elemental composition and the variation in electronic properties as a function of size. In this paper, the effect of the surface plasmons’ contribution to the inelastic scattering is calculated for a simple metal. It is shown that in this particular case the EXAFS analysis performed assuming transferability of the MFP will underestimate coordination numbers in small particles.