Anharmonic Interatomic Potential Parameters Determined via EXAFS Cumulant Analysis for Pt–Fe Nanoparticles in a Polymer Matrix

Resumo

Pt–Fe nanoparticles with a core–shell structure stabilized in polyethylene are studied via X-ray absorption spectroscopy. The temperature-dependent PtL_III-edge EXAFS (extended X-ray absorption fine structure) spectra of nanoparticle nuclei, consisting of platinum atoms, provide information on the interatomic-potential anharmonicity parameters along with the melting point T_melt and the Debye temperature, which are found to be 1630 and 208 K, respectively. This is much lower than for bulk platinum, where the values are 2041.4 and 233 K, respectively.