A many-body Gupta-type potential, derived by fitting bulk experimental parameters for aluminum, has been used to study geometric shell clusters of aluminum with icosahedral, decahedral, fcc, and bcc packing. The stabilities of fcc-like octahedral clusters are compared with cuboctahedral and regularly truncated octahedral clusters. A stepwise pattern of truncation is observed and truncated octahedra are predicted to remain the preferred fcc-like structure until complete transition to the bulk fcc lattice.

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A direct‐space strategy, in which global optimization is carried out on the Rwp hypersurface using a genetic algorithm combined with local minimization of Rwp, has been used to solve the crystal structure of the oligopeptide Phe‐Gly‐Gly‐Phe directly from powder X‐ray diffraction data.

Recent publications have proposed that nucleation in the freezing of supercooled drops occurs at the drop surface, an idea supported by statistical thermodynamic arguments by Cahn [J. Chem. Phys. 1977, 66, 3667] coupled with thermodynamic arguments by Tabazadeh et al. [Proc. Natl. Acad. Sci. U.S.A. 2002, 99, 15873]. Whether this phenomenon is general is examined by molecular dynamics simulations of the freezing of deeply supercooled liquid clusters of SeF6. It is found for this model system that while nucleation occurs not infrequently at the surface, it more often takes place in the interior. The probability for surface nucleation increases with the depth of supercooling. How this relates to theories of Cahn and Tabazadeh et al. is discussed briefly.