Geometric structures of Gen (n=34–39) clusters.

The structures of Gen (n=34–39) clusters were searched by a genetic algorithm using a tight-binding interatomic potential. First-principles calculations based on density functional theory were performed to further identify the lowest-energy structures. The calculated results show that Gen (n=34–39) clusters favor prolate or Y-shaped three-arm structures consisting of two or three small stable clusters (Ge6, Ge7, Ge9, or Ge10) linked by a Ge6 or Ge9 bulk unit. The calculated results suggest the transition point from prolate to Y-shaped three-arm structures appears at Ge35 or Ge36. [ABSTRACT FROM AUTHOR]