A global search algorithm of minima exploration for the investigation of low lying isomers of clusters from density functional theory-based potential energy surfaces: The example of Si(n) (n=3,15) as a test case.

Using an effective generation algorithm coupled with a PBE0/LANL2DZdp level of theory, 905 stable structures of Si(n) (n=3,15) have been found. This global search algorithm of minima exploration includes two original parts: the spheroidal generation, allowing the generation of rings, sphericals, m rings cylinders, and planar structures, and the raking optimization, which discards step by step the conformations that become physically unreasonable during the optimization process. The 142 isomers lying below 1 eV are reported and include the 28 structures reported in the literature. Conformational energies are well reproduced with respect to the values previously published (DeltaE=0,00+/-0,09 eV).