Magnetoresonant softening of solids

The main goal of this work was to detect the magnetosensitive spin-dependent reactions between structural defects and their influence on the plasticity of ionic crystals. It was found that coincidence of quantum energy of a microwave field with the Zeeman splitting energy of electronic spin sublevels of paramagnetic centres leads to an increase in the relaxation rate of assemblages of the defects excited by quenching and, as a result, to resonant weakening of crystals. It means that the electron and nuclear spin states of the defects are of importance in the formation of plasticity in crystals.     

Aspects of the kinetic energy non-additivity in molecular and model subsystems

Several manifestations of the kinetic energy non-additivity are examined and illustrated using model systems. The three different aspects discussed include the density partitioning non-additivity (pn), the subsystem density overlap non-additivity (on), and the so-called particle confinement non-additivity (cn). The possibilities of the marginal decomposition of the many-electron probability distribution are explored in the context of the subsystem resolved theory. The ‘stockholder’ analysis of Hirshfeld is shown to represent a particular, local case of such a decomposition. The two-orbital model of the overlap non-additivity, using the orthogonal orbitals reproducing the subsystem (overlapping) densities, gives explicit functionals for the additive (Weizsäcker-type) and non-additive parts of the kinetic energy. The confinement non-additivity is illustrated using simple non-interacting electron models, including the particle-in-the-box, hydrogen-like atom and the harmonic oscillator. It is shown that in the first case the cn-energy favours the division of electrons among asymmetric sub-boxes, while in the two remaining models the non-additive energy favours placing electrons in equal sub-spaces. The implications for the most efficient matching of the atomic orbitals and the reactant hardnesses are discussed.