Breakdown of the pseudopotential approximation for magnetizabilities and electric multipole moments: test calculations for Au, AuF, and Sn(n) cluster (n ≤ 20).

The response of the electronic wavefunction to an external electric or magnetic field is widely considered to be a typical valence property and should, therefore, be adequately described by accurately adjusted pseudopotentials, especially if a small-core definition is used within this approximation. In this paper we show for atomic Au and Au(+), as well as for the molecule AuF and tin clusters, that in contrast to the case of the static electric dipole polarizability or the electric dipole moment, core contributions to the static magnetizability are non-negligible, and can therefore lead to erroneous results within the pseudopotential approximation. This error increases with increasing size of the core chosen.

The predicted spectrum of the hypermetallic molecule MgOMg.

The present study of MgOMg is a continuation of our theoretical work on Group 2 M(2)O hypermetallic oxides. Previous ab initio calculations have shown that MgOMg has a linear (1)Σ(g)+ ground electronic state and a very low lying first excited triplet electronic state that is also linear; the triplet state has (3)Σ(u)+ symmetry. No gas phase spectrum of this molecule has been assigned, and here we simulate the infrared absorption spectrum for both states.

A systematic search for minimum structures of small gold clusters Au(n) (n=2-20) and their electronic properties.

A systematic search for global and energetically low-lying minimum structures of neutral gold clusters Au(n) (n=2-20) is performed within a seeded genetic algorithm technique using density functional theory together with a relativistic pseudopotential. Choosing the energetically lowest lying structures we obtain electronic properties by applying a larger basis set within an energy-consistent relativistic small-core pseudopotential approach. The possibility of extrapolating these properties to the bulk limit for such small cluster sizes is discussed.

Electronic properties for small tin clusters Sn(n) (n < or = 20) from density functional theory and the convergence toward the solid state.

Global minimum structures of neutral tin clusters with up to 20 atoms obtained recently from genetic algorithm simulations within a density-functional approach (Schäfer et al., J Phys Chem A 2008, 112, 12312) were used to evaluate the corresponding electronic properties. The evolution of these properties with increasing cluster size is discussed in detail and compared with the lighter silicon and germanium clusters.

Structure and electric properties of Sn(N) clusters (N = 6-20) from combined electric deflection experiments and quantum theoretical studies.

Electric deflection experiments have been performed on neutral Sn(N) clusters (N = 6-20) at different nozzle temperatures in combination with a systematic search for the global minimum structures and the calculation of the dielectric properties based on density functional theory. For smaller tin clusters (N = 6-11), a good agreement between theory and experiment is found. Taking theoretically predicted moments of inertia and the body fixed dipole moment into account permits a quantitative simulation of the deflected molecular beam profiles.