"Without the necessary structural information, our understanding of nanocrystals has been limited to models that often treat the surface of a nanocrystal as an extension of a bulk crystalline surface," said University of Illinois Professor Jian-Min Zuo, the study's corresponding author.

Zuo and colleagues used a technique they developed called nano-area coherent electron diffraction. It works by illuminating a single gold nanocrystal with a coherent electron beam about 40 nanometers in diameter.

The electron beam is scattered by the atoms in the nanocrystal, resulting in a complicated diffraction pattern made of speckles. When deciphered, the researchers said the diffraction pattern describes the structural arrangement and behavior of the atoms, and the number and lengths of chemical bonds in the nanocrystal.

The study that included Weijie Huang, Laurent Menard, Jing Tao, Ruoshi Sun and Professor Ralph Nuzzo is to appear in the April issue of the journal Nature Materials and is available at the journal's Web site.