A many-body expansion potential energy function parametrized to the properties of solid germanium is used to study the structures and stabilities of germanium microclusters. Close-packed structures are found for small clusters (Ge2~Ge14), consisting of exclusively four-membered butterfly rings. Shell optimization of the common cubic structures (diamond, s.c., bcc, and fcc) indicates that the distorted s.c., fcc, and bcc shell clusters with the out-most shells compressed most severely are more stable than diamond-type shell clusters and that diamond structures become more stable only for the clusters containing several hundreds of atoms.

Key words: STABILITY, SURFACE STRUCTURE, GERMANIUM, POTENTIAL ENERGY FUNCTIONS