Structural Evolution of Palladium Clusters Pd-Pd: Transition to the Bulk.

We present a study of the structural evolution of palladium cluster anions in a size range from 55 to 147 atoms using a combination of trapped ion electron diffraction and density functional theory computations. We show that Pd clusters ( = 55, 65, 75, 85, 95, 105, and 147) change from an icosahedral motif at Pd to the bulk fcc motif at Pd. This size-dependent structure transition is probed experimentally at a temperature of 95 K and characterized by a continuously increasing fraction of fcc isomers over the considered size range showing a crossover to the fcc motif at ≈ 90.

On the structures of 55-atom transition-metal clusters and their relationship to the crystalline bulk.

Correlation of cluster and bulk structure: Electron-diffraction measurements of homonuclear 55-atom transition-metal cluster anions covering essentially all 3d and 4d elements show only four main structure families. Elements with the same bulk lattice morphology generally have a common cluster structure type. The cluster structure types differ in maximum atomic coordination numbers in analogy to the coordination numbers in the corresponding bulk lattices.

Structures of small bismuth cluster cations.

The structures of bismuth cluster cations in the range between 4 and 14 atoms have been assigned by a combination of gas phase ion mobility and trapped ion electron diffraction measurements together with density functional theory calculations. We find that above 8 atoms the clusters adopt prolate structures with coordination numbers between 3 and 4 and highly directional bonds. These open structures are more like those seen for clusters of semiconducting-in-bulk elements (such as silicon) rather than resembling the compact structures typical for clusters of metallic-in-bulk elements.

Structures of medium sized tin cluster anions.

The structures of medium sized tin cluster anions Sn(n)(-) (n = 16-29) were determined by a combination of density functional theory, trapped ion electron diffraction and collision induced dissociation (CID). Mostly prolate structures were found with a structural motif based on only three repeatedly appearing subunit clusters, the Sn(7) pentagonal bipyramid, the Sn(9) tricapped trigonal prism and the Sn(10) bicapped tetragonal antiprism. Sn(16)(-) and Sn(17)(-) are composed of two face connected subunits.

Structures of tin cluster cations Sn3(+) to Sn15(+).

We employ a combination of ion mobility measurements and an unbiased systematic structure search with density functional theory methods to study structure and energetics of gas phase tin cluster cations, Sn(n)(+), in the range of n = 3-15. For Sn(13)(+) we also carry out trapped ion electron diffraction measurements to ascertain the results obtained by the other procedures. The structures for the smaller systems are most easily described by idealized point group symmetries, although they are all Jahn-Teller distorted: D(3h) (trigonal bipyramid), D(4h) (octahedron), D(5h) (pentagonal bipyramid) for n = 5, 6, and 7.

Jahn-Teller distortions in the photodetachment spectrum of PtCl6(2-): a four-component relativistic study.

In this work the mutual influence of Jahn-Teller (JT) and spin-orbit effects on the photoelectron spectrum of PtCl(6)(2-) is analyzed. For this purpose potential energy surfaces of PtCl(6)(-) along the JT active modes are calculated in the four-component Dirac-Coulomb (DC) framework and the possible JT stabilizations are determined. For the relativistic calculation we set out from the one-particle propagator implemented on the basis of the DC Hamiltonian.

Photodetachment spectra of the PtX(4) (2-) (X=F,Cl,Br) dianions and their Jahn-Teller distortions: A fully relativistic study.

In this work we calculate the photoelectron spectra of the PtX(4) (2-) (X=F,Cl,Br) dianions by application of the third-order Dirac-Hartree-Fock one-particle propagator technique. Relativistic effects and electron correlation are hereby treated on a consistent theoretical basis, which is mandatory for systems containing heavy elements. An experimental PtF(4) (2-) gas phase photoelectron (PE) spectrum is not available and our calculations confirm its instability against autodetachment.