S 70 Sofronov, A. A. The investigation of electron structure and chemical bonding in Ti8C12 met-car [] / A. A. Sofronov, Y. N. Macurin, M. V. Ryzhkov // Physics and chemistry of novel materials: 4th Bilateral Russian-German Symposium (Febr. 24-March 1, 1999): Progr. and abstr. - 1999. - С. 5.3 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): КЛАСТЕРЫ МОЛЕКУЛЯРНЫЕ -- МОЛЕКУЛЯРНЫЕ КЛАСТЕРЫ -- СТРУКТУРА ЭЛЕКТРОННАЯ -- ЭЛЕКТРОННАЯ СТРУКТУРА -- СВЯЗИ ХИМИЧЕСКИЕ -- ХИМИЧЕСКИЕ СВЯЗИ -- РАСЧЕТЫ МАТЕМАТИЧЕСКИЕ -- МАТЕМАТИЧЕСКИЕ РАСЧЕТЫ -- Ti -- ТИТАН -- МЕТКАРЫ -- МЕТАЛЛЫ -- УГЛЕРОД |
I-69 Intrinsic point defects and electron-energetic characteristics of hexagonal monoxide of beryllium [Текст] / A. A. Sofronov, M. A. Gorbunova, Yu. N. Makurin, V. S. Kiiko, A. L. Ivanovskii // Journal of Structural Chemistry. - 2006. - Vol. 47, № 4. - С. 760-763. - Библиогр. : с. 763 (13 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): МОНООКСИД БЕРИЛЛИЯ -- ДЕФЕКТНОСТЬ Аннотация: 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 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)0 ) ~ 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 Полный текст |
E 27 Effect of heat treatment on the electronic spectrum and mechanical properties of BeO ceramics [Text] / M. A. Gorbunova, V. S. Kiiko, A. A. Sofronov, Yu. N. Makurin, A. L. Ivanovskii // Inorganic Materials. - 2006. - Vol. 42, № 10. - P1168-1170. - Библиогр. : с. 1170 (17 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ТЕРМООБРАБОТКА -- ОКСИД БЕРИЛЛИЯ -- КЕРАМИКА Аннотация: The full-potential linear mufin-tin orbital method with a generalized gradient approximation, in conjunction with experimental structural data obtained for BeO ceramics during heatingncooling cycles, was used to analyze the effect of heat treatment on the electronic structure of BeO and to evaluate the thermal expansion coefficients and bulk modulus of BeO ceramics. According to the calculation results, BeO remains a widegap semiconductor in the range 80n300 K, and its band gap varies by no more than ~0.02 eV. The bulk modulus of BeO ceramics (~170 GPa) is 18n25% lower than that of single-crystal BeO. Полный текст |
E 43 Electronic Structure and Chemical Bonding in Crystal and Molecular Titanium Carbides / A. L. Ivanovskii, M. V. Ryzhkov, V. V. Ivanovskaya, A. A. Sofronov, Yu. N. Makurin, G. P. Shveikin // Doklady Physical Chemistry. - 2001. - vol. 378, №1-3. - P129-133 : il. - Bibliogr. : p. 133 (12 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): КАРБИД ТИТАНА -- СТРУКТУРА ЭЛЕКТРОННАЯ -- ХИМИЧЕСКИЕ СВЯЗИ \\\\Expert2\\nbo\\Doklady Physical Chemistry\\2001, V. 378, N 1-3, p.129-133.pdf |
I-98 Ivanovskaya, V. V. Interatomic interactions in cubic nanocrystallite Ti14C13 / V. V. Ivanovskaya, A. A. Sofronov, A. L. Ivanovskii // Journal of Structural Chemistry. - 2001. - Vol. 42, № 4. - P682-685 : il. - Bibliogr. : p. 685 (11 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): КАРБИД ТИТАНА -- НАНОКЛАСТЕРЫ Полный текст |
I-69 Interatomic interactions and electronic structure of NbSe2 and Nb1.25Se2 nanotubes / A. N. Enyashin, V. V. Ivanovskaya, I. R. Shein, Yu. N. Makurin, N. I. Medvedeva, A. A. Sofronov, A. I. Ivanovskii // Journal of Structural Chemistry. - 2004. - Vol. 45, № 4. - P547-556 : il. - Bibliogr. : p. 555-556 (42 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): НАНОТРУБКИ -- ДИСЕЛЕНИД НИОБИЯ -- МЕЖАТОМНОЕ ВЗАИМОДЕЙСТВИЕ Аннотация: Atomic models of achiral NbSe2 nanotubes are suggested. Band structure calculations have been performed to investigate the electronic structure and determine the parameters of interatomic interactions. The distribution of the density of states and pair bond occupancies of NbSe2 nanotubes are analyzed in relation to the type of the atomic configuration and the tube diameter; the results are compared with the band structure of the 2-NbSe2 crystal. Calculations have been carried out on hypothetical “superstoichiometric” nanotubes with a formal composition Nb1.25Se2 as possible quasi-one-dimensional nanoforms of autointercalated niobium diselenide Полный текст |
I-98 Ivanovskii, A. L. Electronic Structure and Chemical Bonds in Titanium Dicarbide with Disordered C2 Dimers / A. L. Ivanovskii, N. I. Medvedeva, A. A. Sofronov // Russian Journal of Coordination Chemistry. - 2001. - Vol. 27, № 2. - P112-115 : il. - Bibliogr. : p. 114-115 (18 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ДИКАРБИД ТИТАНА -- СТЕХИОМЕТРИЯ Аннотация: A quantum–chemical zone and cluster approaches were used to model the electronic energy spectrum and to study the chemical bond in a hypothetical phase of titanium dicarbide (TiC2) composed of C2 dimers as structural units. The effect of orientational disorder of the C2 dimers on the electronic structure and chemical stability of the dicarbide was investigated Полный текст |
T 44 The Electronic Structure of Mixed Metcars Ti7MC12 (M = Y, Zr, Nb, …, Ag) / A. A. Sofronov, V. V. Ivanovskaya, Yu. N. Makurin, A. L. Ivanovskii // Russian Journal of Coordination Chemistry. - 2001. - Vol. 27, № 11. - P808-818 : il. - Bibliogr. : p. 818 (34 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): МЕТКАРЫ -- ЭЛЕКТРОННАЯ СТРУКТУРА -- СТЕХИОМЕТРИЯ Аннотация: The electronic structures of a series of mixed metallocarbohedrenes (metcars) T7MC12 formed as a result of replacement of the titanium atom in the Ti8C12 metcar by 4d transition metal ions (M = Y, Zr, Nb, É, Ag) are established using the ab initio electron density functional method in the discrete-variational scheme. The dependences of electronic structure, charge distributions, and chemical bonds in the Ti7MC12 metcars on the cluster symmetry (Th or Td) and position of the 4d atom in a molecular cage are discussed. The electronic states of 4d atoms in molecular titanium carbide (Ti8C12 metcar) are compared with those in crystal titanium carbide (cubic TiC phase with rock salt structure). The effect of doping of the T8C12 metcar with 4d atoms on its reactivity is studied. Полный текст |
E 43 Electronic Properties and Chemical Bonds of 3d Atoms in Carbon Nanotubes and Metallocarbohedrenes / A. A. Sofronov, V. V. Ivanovskaya, Yu. N. Makurin, A. L. Ivanovskii // Russian Journal of Coordination Chemistry. - 2002. - Vol. 28, № 9. - P618-629 : il. - Bibliogr. : p. 628-629 (29 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): НАНОТРУБКИ КАРБОНОВЫЕ -- ФУЛЛЕРЕНЫ -- КАРБИД ТИТАНА Аннотация: The electronic states of 3d atoms (M = Ti, Cr, Fe, and Cu) intercalated into the bulk of carbon nanotubes (NT) or replacing the titanium atom in carbohedrene Ti8C12 are studied by the ab initio self-consistent discrete variation method. The electronic state, charge distributions, and parameters of interatomic interactions are analyzed in nanotubular composites M@NT depending on the NT structure ((9.0) or (4.4)) and position of the M atom (at the end or in the center of the NT) and depending on the cluster symmetry (Th or Td) and positions of M atoms in the metal–carbon cage for “substituted” metcars Ti7MC12. Possible changes in some physicochemical properties of the nanotubes and metallocarbohedrenes with the indicated 3d atoms are discussed Полный текст |
Q 23 Quantum-Chemical Simulation of New Hybrid Nanostructures: Small Fullerenes C20 and C28 in Single-Walled Boron-Nitrogen Nanotubes / V. V. Ivanovskaya, A. N. Enyashin, A. A. Sofronov, Yu. N. Makurin, A. L. Ivanovskii // Russian Journal of General Chemistry. - 2004. - Vol. 74, № 5. - P713-720 : il. - Bibliogr. : p. 719-720 (33 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): КВАНТОВО-ХИМИЧЕСКОЕ МОДЕЛИРОВАНИЕ -- ФУЛЛЕРЕНЫ -- НАНОТРУБКИ БОРОНИТРИДНЫЕ Аннотация: A quantum-chemical simulation of new hybrid nanostructures consisting of regular chains of the small fullerenes C20 and C28 encapsulated into the bulk of achiral zigzag single-walled boron-nitrogen nanotubes [(C20,C28)@BN-NT]. The electronic properties and the nature of interatomic bonds in these nanostructures are analyzed as a function of the fullerene and the distances between fullerenes in the chain and between fullerenes and tube walls. The electronic characteristics of hybrid nanostructures are compared with those of "isolated" fullerenes and nanotubes, and (C20,C28) + BN-NT structures simulating fullerene adsorption on tube surface as the initial stage of (C20,C28)@BN-NT formation Полный текст |
I-98 Ivanovskaya, V. V. New quasi-one-dimensional crystals of metallocarbohedrenes (Sc,Ti,V)8C12 in (12,0) boron-nitrogen nanotubes: quantum-chemical simulation / V. V. Ivanovskaya, A. A. Sofronov, A. L. Ivanovskii // Theoretical and Experimental Chemistry. - 2001. - Vol. 37, № 6. - P333-337 : il. - Bibliogr. : p. 337 (10 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): НАНОТРУБКИ БОР-АЗОТНЫЕ -- КВАНТОВО-ХИМИЧЕСКОЕ МОДЕЛИРОВАНИЕ Аннотация: A quantum-chemical model was made of new quasi-one-dimensional crystals, consisting of regular chains of metallocarbohedrenes Sc8C12, Ti8C12, and V8C12 (isomers with Th symmetry) inside a single-wall (12,0) boron-nitrogen nanotube. Their electronic characteristics, the nature of the interatomic bonds, and the relative stability in relation to the electronic concentration in the (Sc8C12@(12,0)BN-NT ® Ti8C12@(12,0)BN-NT ® V8C12@(12,0)BN-NT) systems and the mutual arrangement of the metallocarbohedrenes and the nanotube are discussed Полный текст |
Q 23 Quantum-chemical modelling of the electronic structure and the chemical bond in multiwalled nanotubes based on metal diborides / V. V. Ivanovskaya, A. N. Enyashin, A. A. Sofronov, Yu. N. Makurin, N. I. Medvedeva, A. L. Ivanovskii // Theoretical and Experimental Chemistry. - 2003. - Vol. 39, № 1. - P1-8 : il. - Bibliogr. : p. 7-8 (18 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): КВАНТОВО-ХИМИЧЕСКОЕ МОДЕЛИРОВАНИЕ -- НАНОТРУБКИ -- ДИБОРИДЫ МЕТАЛЛОВ Аннотация: A quantum-chemical model of multiwalled nanotubes of magnesium diboride was produced. The electronic structure and the nature of the interatomic bonds in the multiwalled nanotubes were studied in relation to the diameter and the number of Mg-B2 layers: (6,6)-> (3,3) ® (6,6)@(12,12) ->(3,3)@(6,6)@(12,12). Possible methods for the production of diboride nanotubes are discussed. Features of the electronic states in composite nanotubular structures based on the diborides of s and p metals are examined for the first time as illustrated by the(6,6)AlB2(12,12)MgB2 multiwalled nanotube Полный текст |