Geometry optimization of triply charged yttrium-doped helium clusters:: HenY3+

Global minima of the Coulomb-stable clusters HenY3+ were calculated using a simulated annealing procedure based on state-of-the-art two-body potentials for the He-Y3+ and He-He pair interactions, and compared with subsequent density-functional theory (DFT). Both approaches yield very similar symmetries for the global minima up to a number of 12 helium atoms when occupation of the second helium shell becomes more favorable at the DFT level. In the simulated annealing two-body approach the second shell is occupied from atom 17 onwards. Both methods predict an exceptional stability for the icosahedral cluster He12Y3+. (C) 2002 American Institute of Physics.