CuBr Cluster Restructuring

The reaction of Br₂ with Cu(100) surfaces creates epitaxial CuBr(111).   In this movie of a Cu surface vicinal to (100), the CuBr is readily identifiable by its higher step height than Cu and its cluster edges that meet at 120^o.   In this movie, the CuBr cluster formed by aggregation of two CuBr clusters restructures to form a more compact structure.  The more compact structure decreases the edge length and energy and is thus thermodynamically favored.