Modeling of the structure and electronic structure of condensed phases of small fullerenes C<Subscript>28</Subscript> and Zn@C<Subscript>28</Subscript>

A comparative analysis of the stability factors and electronic structure of two possible crystalline forms of small fullerene C₂₈ and endohedral fullerene Zn@C₂₈ with diamond and lonsdaleite structures is performed using a cluster model. Atoms of elements that, when placed inside C₂₈ cages, have no significant effect on the stability of free small-fullerene molecules are shown to be able to dramatically change the electronic properties and reactivity of the C₂₈ skeleton and to be favorable for forming small-fullerene crystalline modifications, which are covalent crystals. In contrast, if the presence of foreign atoms inside C₂₈ cages stabilizes the isolated nanoparticles, then molecular crystals (such as C₆₀ fullerites) are formed due to weak van der Waals forces.     

Calculation of the relative activation energies for reactions forming metal sulfides

Theoretical and Experimental Chemistry -     

Intrinsic point defects and electron-energetic characteristics of hexagonal monoxide of beryllium

Using the zone method of a linear combination of plane waves for the supercell model, there have been studied energy and electron states of beryllium monoxide BeO with intrinsic point defects: the vacancy in the sub-lattice of beryllium + interstitial atom of Be {V_Be + Be_i}. The most stable among the considered configurations of defects are the vacancies and interstitial atoms of beryllium Be _i ^o occupying octahedral positions at R(V_Be-Be _i ^o ) ～ 3.15–3.35 Å distances from each other. Depending on the configuration of defects, the forbidden gap of beryllium oxide can change by ～0.4–2.4eV.     

Effect of Li and Na impurities on the electronic and magnetic properties of beryllium oxide

The ab initio pseudopotential method (VASP package) within the gradient approximation (GGA) for the exchange-correlation potential is used to study the effect of Li and Na substitution for Be atoms on the electronic and magnetic properties of wurtzite-like beryllium monoxide BeO with an impurity concentration of 0.028. When Li impurity is introduced into BeO, the system is found to remain nonmagnetic. At the same time, the BeO:Na system adopts magnetic moments (~0.8 fu_B per cell) through the spin polarization of the 2p-state of oxygen atoms surrounding the impurity center. After lithium incorporation into BeO, the spectrum of BeO:Li becomes metal-like, while the introduction of sodium results in the magnetic semimetal type of the BeO:Na spectrum     

Reaction of Metcar Ti8C12 with Halogen-Containing Addends

Ab initio electron density functional method in the discrete-variational scheme was used to perform self-consistent calculations of the electronic structure of Ti₈C₁₂Cl₂ and Ti₈C₁₂(CHCl₃), i.e., the adducts of reaction between the Ti₈C₁₂ metallocarbohedrene and halogen-containing addends (Cl₂ and CHCl₃ molecules). The electronic states, charge distributions, and chemical bonds of the obtained adducts were analyzed. The results were compared with calculations of the Ti₈C₁₂Cl complex that can be treated as a model of the destruction stage of the addends. General conditions for the interaction of halogenated addends with metcars in the molecular and crystalline states are discussed based on the data obtained.