Structure of gold nanoparticles suspended in water studied by x-ray diffraction and computer simulations

Gold nanoparticles with an average size of 3 nm, 15 nm, and 30 nm suspended in water have been studied by x-ray diffraction and computer simulations. The atomic pair distribution function approach was employed to determine the three-dimensional structure because of the limited structural coherence in these nanostructured materials. The nanoparticles possess a well-defined atomic arrangement resembling the face-centered cubic (fcc) structure occurring with bulk gold. The fcc-type features of this arrangement become more prominent with increasing nanoparticle size. The study provides a clear picture of the nanoparticles' size-structure relationship and can help open up the route for calculating and predicting of their useful properties.