Abstract
Decahedral multiply-twinned particles of Si, 60–80 nm in size, prepared by a gas evaporation method are studied by a high resolution electron microscope. A mismatch arising in packing five tetrahedra is accommodated by deforming plastically one of the tetrahedra by introducing a small angle grain boundary. A core region of the particle, however, is deformed elastically. The structural details of the crystalline faults associated with the mismatch are described.