Influence of electronic and geometric properties on melting of sodium clusters

Systematics of the melting transition for sodium clusters with 40-355 atoms has been studied with both ab initio and semiclassical molecular dynamics simulations. The melting temperatures obtained with an ab initio method for Na55 + and Na93 + correlate well with the experimental results. The semiclassically determined melting temperatures show similarities with the experimentally determined ones in the size region from 55 to 93 and near size 142, and the latent heat in the size region from 55 to 139, but not elsewhere in the size region studied. This indicates that the nonmonotonical melting behavior observed experimentally cannot be fully explained by geometrical effects. The semiclassica…

Stacking faults in close-packed clusters

Ground state geometries of small hard sphere clusters were studied using two different type of contact interaction, a pair-potential and a many-atom interaction. Monte Carlo method in an FCC lattice with all possible (111) stacking faults was used to obtain the minimum energy geometries for clusters up to 59 atoms. Due to the surface energy, FCC packing is generally favoured as opposite to the HCP structure. However, in most cluster sizes the ground state obtained with the many-atom interaction has one or more stacking faults. The most symmetric geometry is usually not the ground state. Clusters with 59 and 100 atoms were studied due the possibility of a high symmetry cluster with stacking …

A small spherical liquid: A DFT molecular dynamics study of WAu12

The finite-temperature dynamics of WAu12, incorporating both electronic and structural effects, is studied using a density-functional-based Born-Oppenheimer molecular dynamics method. Molecular dynamics simulations for monomolecular WAu12 suggest a surface-melting-type behaviour of the angular degrees of freedom between 366 and 512 K. Thermally averaged electron density-of-states of WAu12 are compared to the experimental photoelectron spectra of WAu12(-).

Studies of structures and melting of small metal clusters