Analytic Alchemical Derivatives for the Analysis of Differential Acidity Assisted by the Function.

Analytical calculation of alchemical derivatives based on auxiliary density perturbation theory is described, coded, and validated. For the case where the nucleus is a hydrogen atom and the nuclear charge is changed from 1 to 0, it turns out that a good estimate of the proton binding energies can be obtained very efficiently. First-order results correspond exactly to the molecular electrostatic potential evaluated at the hydrogen nucleus location (removing self-repulsion), in agreement with previously reported extensive studies.

Nature of valence transition and spin moment in Ag(n)V(+) clusters.

Evolution in the atomic structure, bonding characteristics, stability, and the spin magnetic moment of neutral and cationic AgnV clusters has been investigated using first-principles density functional approach with gradient corrected functional. It is shown that at small sizes, the V 4s states hybridize with Ag states to form 1S and 1P like superatomic orbitals, whereas the 3d states are localized on V giving the V atom an effective valence of 1 or 2. Starting from Ag8V(+), the V 3d states begin to participate in the bonding by hybridizing with the nearly free electron gas to form 1D superatomic orbitals increasing the V atom effective valence toward 5.

Robust magnetic moments on impurities in metallic clusters: localized magnetic states in superatoms.

Introducing magnetic impurities into clusters of simple metals can create localized states for higher angular momentum quantum numbers (l = 2 or 3) that can breed magnetism analogous to that in virtual bound states in metallic hosts, offering a new recipe for magnetic superatoms. In this work, we demonstrate that MnCa(n) clusters containing 6-15 Ca atoms show a spin magnetic moment of 5.0 μB irrespective of the cluster size.

Metallic and molecular orbital concepts in XMg8 clusters, X = Be-F.

The electronic structure and stability of the XMg(8) clusters (X = Be, B, C, N, O, and F) are studied using first principles theoretical calculations to understand the variation in bonding in heteroatomic clusters which mix simple divalent metals with main group dopants. We examine these progressions with two competing models, the first is a distorted nearly free electron gas model and the second is a molecular orbital picture examining the orbital overlap between the dopant and the cluster. OMg(8) is found to be the most energetically stable cluster due to strong bonding of O with the Mg(8) cluster.

Hund's rule in superatoms with transition metal impurities.

The quantum states in metal clusters bunch into supershells with associated orbitals having shapes resembling those in atoms, giving rise to the concept that selected clusters could mimic the characteristics of atoms and be classified as superatoms. Unlike atoms, the superatom orbitals span over multiple atoms and the filling of orbitals does not usually exhibit Hund's rule seen in atoms. Here, we demonstrate the possibility of enhancing exchange splitting in superatom shells via a composite cluster of a central transition metal and surrounding nearly free electron metal atoms.