A structure for the nanoalloy Ag3Au10 has been identified by a combination of genetic algorithm global optimization and density functional theory (DFT) calculations. The global minimum of the Ag3Au10 cluster is identified as a wedge-shaped nanoshell with C-s point group symmetry. The infrared spectrum and optical absorption spectra of the ground state structure are also investigated by DFT calculations within the local density approximation. The optical absorption spectrum of the Ag3Au10 nanoalloy has four absorption peaks at 2.18, 2.92, 3.28, and 3.60 eV, which contrasts with pure Ag-13 and Au-13 clusters. (c) 2007 American Institute of Physics.