Muon states in uniaxially strained iron

Effects of lattice relaxation, quantum motion, and uniaxial strain on the internal field at a positive-muon site in iron have been calculated. The uniaxial strain gives rise to a statistical shift of the muon population at interstitial sites. The effect of the population shift is found to be primarily responsible for the observed changes in the muon-precession frequency. The theory also predicts a 1T temperature dependence of the frequency shifts. Peer reviewed

Spontaneous fragmentation of multiply charged metal clusters.

Role of elastic and electronic interactions in trapping of hydrogen by impurities in transition metals

The interplay between the lattice distortion and the electronic contributions to the trapping of migrating hydrogen isotopes by substitutional impurities is investigated. We use a comprehensive calculational scheme incorporating (i) the effective-medium theory for the electronic interaction, (ii) the lattice Green’s function for elastic coupling, and (iii) the hydrogen quantum motion. The calculations for Ti and Cr impurities in V host show that lattice strain effects dominate. Cr, which otherwise provides an electronic trap site, does not induce trapping when elastic effects are incorporated. The situation in the case of Ti is just the reverse. We find no isotope dependence of the binding …

Clusters-a New Source for Atomically Engineered Materials

ABSTRACTThe electronic structure and properties of small clusters are strongly dependent on their size. These size specific properties are illustrated by confining the discussion to three different topics (1) interaction of hydrogen with clusters (2) effect of temperature and magnetic field on the magnetization of clusters and (3) reaction of clusters with gas atoms. It is shown that the electronic energy levels that are strongly dependent on cluster size give rise to the size specific electronic properties of clusters. In cluster hydrides certain elements are found to absorb more hydrogen per atom in cluster form than in a crystalline form. The magnetization of clusters increases as a func…

Hydrogen and deuterium decoration of In-vacancy complexes in nickel.

The quantum-mechanical states of hydrogen and deuterium in pure and defected nickel have been calculated using the effective-medium theory. The defects considered include monovacancies, the substitutional In impurity, a complex of four vacancies, and a complex of an In impurity decorated with a tetrahedron of four vacancies. While the substitutional In impurity does not trap hydrogen, the vacancy and the vacancy complexes with and without In association do. The calculated binding energy to the four vacancy complex is nearly insensitive to the hydrogen isotopic mass and to the In decoration. These results, along with the dependence of the hydrogen binding energy on multiple hydrogen occupanc…