Abstract
X-ray absorption spectroscopy measurements have been made on 7-, 12-, and 23-nm palladium particles, along with bulk material as reference. With decreasing particle size, the extended x-ray absorption fine spectra reveal a substantial contraction of the nearest-neighbor distance and a reduction of the average coordination number, but an increasing Debye-Waller factor. Meanwhile, the x-ray absorption near edge spectra show a decreasing density of unoccupied states with decreasing particle size. © 2007 The American Physical Society.