E 43 Electronic structure and chemical bonding in polymorphs of bismuthsesquioxide [] / V. P. Zhukov, V. M. Zhukovsky, V. M. Zainullina, N. I. Medvedeva // Physics and chemistry of novel materials: 4th Bilateral Russian-German Symposium (Febr. 24-March 1, 1999): Progr. and abstr. - 1999. - С. 2.33 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): СТРУКТУРА ЭЛЕКТРОННАЯ -- ЭЛЕКТРОННАЯ СТРУКТУРА -- СВЯЗИ ХИМИЧЕСКИЕ -- ХИМИЧЕСКИЕ СВЯЗИ -- Bi -- ВИСМУТ -- ЛМТО МЕТОД -- МЕТОД ХЮККЕЛЯ -- ВЗАИМОДЕЙСТВИЕ МЕЖАТОМНОЕ -- МЕЖАТОМНОЕ ВЗАИМОДЕЙСТВИЕ -- ХЮККЕЛЯ МЕТОД |
Z 18 Zainullina, V. M. Electronic structure and ionic conductivity in ZrO2, ZrO2-CaO, ZrO2-Y2O3 by the ab initio LMTO-TB supercell approach [] / V. M. Zainullina, V. P. Zhukov, V. M. Zhukovsky // Physics and chemistry of novel materials: 4th Bilateral Russian-German Symposium (Febr. 24-March 1, 1999): Progr. and abstr. - 1999. - С. 2.32 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): СТРУКТУРА ЭЛЕКТРОННАЯ -- ЭЛЕКТРОННАЯ СТРУКТУРА -- ПРОВОДИМОСТЬ ИОННАЯ -- ИОННАЯ ПРОВОДИМОСТЬ -- ЛМТО МЕТОД -- ZrO2 -- Zr -- ЦИРКОНИЙ -- ОКСИД ЦИРКОНИЯ -- ПРОВОДИМОСТЬ -- CaO -- ОКСИД КАЛЬЦИЯ -- Ca -- КАЛЬЦИЙ -- Y2O3 -- ОКСИД ИТТРИЯ -- Y -- ИТТРИЙ |
E 43 Electronic structure and chemical bonding in K2V3O8 [Текст] / V. M. Zainullina, V. L. Volkov, N. V. Podvalnaya, A. L. Ivanovskii // Journal of Structural Chemistry. - 2005. - Vol. 46, № 2. - С. 340-342. - Библиогр. : с. 342 (14 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ПОЛИВАНАДАТ КАЛИЯ -- ИОННАЯ ПРОВОДИМОСТЬ Аннотация: The calculations of the electronic structure of layered polyvanadate K2V3O8 were made employing the spinpolarized tight-binding LMTO method. Calculated magnetic moment for K4V6O16 compound phase equals 1.97 мB. V-O interactions were established to be dominating in the chemical bonding generation in this polyvanadate according to the estimated crystal orbital overlap population. The covalent bonds V(2)-V(2) in V(2)2O7 groups and electron density localization on vanadium atoms in isolated pyramids V(1)O were found. Полный текст |
V 58 Vibrational spectra of tin and lead cyanoferrate(II) and cyanoferrate(III) complexes [Текст] / T. A. Denisova, L. G. Maksimova, S. A. Kovyazina, E. V. Polyakov, V. M. Zainullina, N. A. Zhuravlev, V. G. Zubkov, A. P. Tyutyunnik, O. V. Koryakova // Zhurnal Neorganicheskoi Khimii. - 2004. - Vol. 49, № 9. - С. 1531-1537 Рубрики: ХИМИЧЕСКИЕ НАУКИ |
P 36 Peculiarities of Chemical Binding in Anhydrous Lead(II) and Tin(II) Hexacyanoferrates(II,III) [Текст] / V. M. Zainullina, V. P. Zhukov, V. G. Zubkov, A. P. Tyutyunnik, L. G. Maksimova, T. A. Denisova // Journal of Structural Chemistry. - 2004. - Vol. 45, № 2. - С. 201-205. - Библиогр. : с. 205 (7 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ЭЛЕКТРОННАЯ СТРУКТУРА -- ГЕКСАЦИАНОФЕРРАТЫ Аннотация: The electronic structure and chemical binding of anhydrous lead and tin hexacyanoferrates(II,III) Pb2Fe(CN)6, Pb1.5Fe(CN)6, and Sn2Fe(CN)6 were studied by the linear muffm-tin orbital (tight binding approximation) and extended Hückel theory methods. The general tendencies of variation for the stability of the Pb–N, Sn–N, Fe–C, and C–N bonds were determined for Pb2Fe(CN)6, Pb1.5Fe(CN)6, and Sn2Fe(CN)6 crystals. Peculiarities of Pb(Sn)–N chemical interactions in the structure of the phases have been found Полный текст |
Z 18 Zainullina, V. M. Electronic and magnetic structures and conductivity of strontium ferrite. An ab initio LSDA + U approach [Текст] / V. M. Zainullina, M. A. Korotin, V. L. Kozhevnikov // Russian Journal of Electrochemistry. - 2007. - Vol. 43, № 5. - С. 570-575. - Библиогр. : с. 575 (16 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ФЕРРИТ СТРОНЦИЯ -- ЭЛЕКТРОННАЯ СТРУКТУРА Аннотация: Using the first-principle nonempirical linear muffin-tin orbital method in the tight-binding approximation (TB-LMTO) to the LSDA + U approximation, the electronic and magnetic structures and defect formation in strontium ferrite Sr3Fe2O6 are studied. It is found that Sr3Fe2O6 is a G type antiferromagnetic with the semiconductor electronic structure. The calculated band gap of 1.82 eV agrees well with experimental value (~2 eV). The ferrite spectrum corresponds to that of a semiconductor with a band gap of charge transfer. Iron ions in Sr3Fe2O6 are in a high-spin state and have configuration t2g↑3 eg↑2 eg↓1. The calculated local magnetic moment on the iron ions is 3.9μB. The presence of iron ions with a magnetic moment approaching 4μB in Sr3Fe2O6 is explained by strong hybridization of 3d orbitals of iron and 2p orbitals of oxygen. The high-spin state of iron ions is described by d5+d6L states with predominant contribution d6L, where L is a hole on oxygen. Based on ab initio LSDA + U calculations, various types and configurations of defects in the oxygen sublattice (oxygen vacancies, anti-Frenkel defects) are studied and a model for ionic transport in Sr3Fe2O6is proposed Полный текст |
O-97 Oxide ceramics BIMEVOX: Conductivity, structure, and chemical bond [Текст] / V. M. Zhukovskii, Yu. V. Emel'yanova, R. R. Shafigina, S. A. Petrova, V. M. Zainullina, E. S. Buyanova // Russian Journal of Electrochemistry. - 2007. - Vol. 43, № 4. - С. 443-447. - Библиогр. : с. 447 (4 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ВАНАДАТ ВИСМУТА -- КИСЛОРОДНО-ИОННЫЕ ПРОВОДНИКИ -- КВАНТОВО-ХИМИЧЕСКИЕ РАСЧЕТЫ Аннотация: The processes of synthesis, ranges of stable existence, structure, and migration characteristics of complex oxides of the BIMEVOX series are studied experimentally and theoretically. Полный текст |
Z 18 Zainullina, V. M. Electronic structure, chemical bonding and properties of Sn1-xMxO2, M = As, Sb, Bi, V, Nb, Ta (0.0 = x = 0.25) [Текст] / V. M. Zainullina // Physica B: Condensed Matter (Amsterdam, Netherlands). - 2007. - Vol. 391, № 2. - С. 280-285 Рубрики: ХИМИЧЕСКИЕ НАУКИ |
O-97 Oxide ion conductors of the BIMEVOX family: synthesis, structure, and conductivity [Text] / Yu. V. Emel'yanova, R. R. Shafigina, E. S. Buyanova, V. M. Zhukovskii, V. M. Zainullina, S. A. Petrova // Russian Journal of Physical Chemistry. - 2006. - Vol. 80, № 11. - P1725-1730. - Библиогр. : с. 1730 (13 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ИОННЫЕ ПРОВОДНИКИ -- КВАНТОВО-ХИМИЧЕСКИЕ РАСЧЕТЫ Аннотация: The synthesis, stable existence regions, structure, and migration characteristics of complex oxides of the BIMEVOX family were studied experimentally and theoretically. The temperature, composition, and oxygen partial pressure dependences of the conductivity of the samples obtained were determined. The contribution of oxide ion transport decreased as the temperature and oxygen partial pressure lowered. Quantum-chemical calculations of β-Bi4V2O11and γ-Bi4V2O11 were performed to analyze the relative stabilities of the phases and the influence of dopants Полный текст |
Z 18 Zainullina, V. M. Electronic structure and properties of strontium ferrite Sr3Fe2O6 [Text] / V. M. Zainullina, M. A. Korotin, V. L. Kozhevnikov // European Physical Journal B: Condensed Matter Physics. - 2006. - Vol. 49, № 4. - P425-431. - Библиогр. : с. 431 (18 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ЭЛЕКТРОННАЯ СТРУКТУРА -- ФЕРРИТ СТРОНЦИЯ Аннотация: The electronic structure of strontium ferrite Sr3Fe2O6 was calculated using the tight-binding linear muffin-tin orbital method (TB LMTO) in the local spin density approximation of density functional theory with Coulomb correlations correction (LSDA+U). The semiconducting character of the spectrum with charge transfer energy gap of 1.82 eV was obtained in reasonably good agreement with experimental data. The iron ions are found to be in the high spin state. The calculated value of the local spin magnetic moment of Fe3+ ion is 3.94 μB which is not typical for trivalent iron ion in the high spin state. It is shown that the strong hybridization between Fe3d and O2p orbitals favors the d6L configuration of Fe3+ ion, where L is a hole in the oxygen p shell. The mechanism of oxygen transport in ferrite is discussed basing on the total energy calculations of the different spatial configurations of oxygen vacancies Полный текст |
Z 18 Zainullina, V. M. Investigation of the Electronic Structure and Chemical Bonding of Lead Hexacyanoferrate(III) [Text] / V. M. Zainullina, M. A. Korotin, L. G. Maksimova // Physics of the Solid State. - 2004. - Vol. 46, № 10. - P1836-1841. - Bibliogr. : p. 1840-1841 (18 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ЭЛЕКТРОННАЯ СТРУКТУРА -- ГЕКСАЦИАНОФЕРРАТЫ Аннотация: The electronic structure of lead hexacyanoferrate(III) is calculated by the ab initio tight-binding linear muffin-tin orbital (TB-LMTO) method in the LSDA + U approximation. The influence of vacancies in the lead sublattice on the electronic spectrum, chemical bonding, and magnetic properties of the Pb1.5Fe(CN)6 phase is investigated. Analysis of the electronic spectrum shows that this compound is characterized by semi-conductor conductivity. It is demonstrated that the semiconductor gap is associated with the charge ordering of iron(III) ions. Полный текст |
T 44 The electronic structure and properties of Ni1-xLixO1-y (0=x=1/4, 0=y=1/8) [Текст] / V. M. Zainullina, M. A. Korotin, Yu. P. Zaikov, N. I. Shurov // Solid State Sci. - 2004. - Vol. 6, № 10. - С. 1139-1148 Рубрики: ХИМИЧЕСКИЕ НАУКИ |
S 61 Zhukov, V. P. First-principles calculations of the electronic structure of fluorite-type crystals (CaF2, BaF2, SrF2, and PbF2) containing Frenkel defects. Analysis of optical and transport properties [Text] / V. P. Zhukov, V. M. Zainullina // Physics of the Solid State. - 1998. - Vol. 40, № 11. - P1827-1832 : il. - Bibliogr. : p. 1832 (36 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ЭЛЕКТРОННАЯ СТРУКТУРА -- ФТОРИДЫ ЩЕЛОЧНОЗЕМЕЛЬНЫХ ЭЛЕМЕНТОВ -- ДЕФЕКТ ФРЕНКЕЛЯ -- ЛМТО МЕТОД Аннотация: The electronic structure of the alkali-earth fluorides CaF2, BaF2, SrF2, and PbF2 with Frenkel defects is investigated in the tight-binding approximation by the LMTO method. The defect formation and migration energies are calculated. The electronic structure and optical excitations of a H center in a defective fluorite structure are examined. It is shown on the basis of calculations of the binding energies that CaF2, BaF2, and SrF2 are ionic compounds, while the chemical bond in PbF2 is partially covalent. Possible methods of displacement of interstitial fluorine atoms that lead to the observed optical spectra of an H center are investigated Полный текст |
E 43 Electronic structure and chemical bonding in Sr4Nb17O26 / V. M. Zainullina, V. P. Zhukov, V. G. Zubkov, A. P. Tyutyunnik // Journal of Structural Chemistry. - 1998. - Vol. 39, № 5. - P627-635 : il. - Bibliogr. : p. 634-635 (15 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ОКСОНИОБАТ СТРОНЦИЯ -- МЕТОД ЛМТО Аннотация: The electronic structure of oxoniobate Sr4Nb17026 is studied by the linear muffin-tin orbital (LMTO) method. It is shown that the high-energy conduction band consists of the Nb4d states and the hybridized valence band is formed by the Nb4d and 02p states. The band structure of this compound is characterized by superposition of the bands of the 2p states of perovskite oxygen atoms and the 4d states of monoxide niobium atoms. The degree of oxidation of the perovskite and monoxide niobium atoms is + 5 and + 2.56, respectively. Chemical bonding is analyzed using the electron localization function and model Hiickel calculations. The niobium-oxygen bond is shown to be the strongest. The Fermi level is localized in the vicinity of the bottom of the niobium antibonding state band, which explains the existence of Sr4-xNb17026 in the homogeneity region corresponding to 0 < x < 0.3 Полный текст |
E 43 Electronic structure and chemical bonding in bismuth sesquioxide polymorphs / V. P. Zhukov, V. M. Zhukovskii, V. M. Zainullina, N. I. Medvedeva // Journal of Structural Chemistry. - 1999. - Vol. 40, № 6. - P831-837 : il. - Bibliogr. : p. 837 (23 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ЛМТО МЕТОД -- ОКСИД ВИСМУТА Аннотация: The electronic structure of the alfa-Bi203 . beta-Bi203 and gamma-Bi203 phases was investigated by the ab initio sell-consistent LMTO method in a tight bindbtg approximation attd by the sent iempbical Hiickel method. The total and partial densities of states and Mulliken overlap populations were obtained. The stability of bismuth oxide polymorphs is discussed based on the results of the total energy calculations for crystals. An analysis of chemical bonding shows that the Bi-O interaction plays the leading role. The Bi-Bi metallic bond is absent. Mechanisms of oxygen ion migration and possible stabilization of the structure of the supelionic conductor beta-Bi20 3 are discussed Полный текст |
E 43 Electronic structure and ionic in calcium- and zirconium dioxide / V. M. Zainullina, V. P. Zhukov, V. M. Zhukovskii, N. I. Medvedeva // Journal of Structural Chemistry. - 2000. - Vol. 41, № 2. - P185-193 : il. - Bibliogr. : p. 192-193 (32 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ОКСИД ЦИРКОНИЯ -- ОКСИД КАЛЬЦИЯ -- ТВЕРДЫЕ РАСТВОРЫ Аннотация: The electronic structure, chemical bonding, and ionic transport were investigated for ZrO2 polymolphs and solid solutions ZrO2-CaO and ZrO2-Y203 using the LMTO ab initio self-consistent method in a tight binding approximation and Hiickel's semiempiriical method. In stabilized zirconium dioxide, ionic conductivity is mainly due to vacancies in the oxygen sublattice. The mechanism of stabilization of the fluorine structure by calcium and yttrium intpurities is considered. The nonlinear variation of the ionic conductivitv of ZrO2 is interpreted as a function of the phase composition of solid solutions. The clustetization is first supported by ab initio calculations \\\\Expert2\\nbo\\Journal of Structural Chemistry\\2000, V. 41, N 2, P.185-193.pdf |
I-98 Ivanovskii, A. L. Chemical binding and electronic structure of fluorite-like zirconium oxynitrides / A. L. Ivanovskii, V. M. Zainullina, S. V. Okatov // Journal of Structural Chemistry. - 2000. - Vol. 41, № 4. - P553-559 : il. - Bibliogr. : p. 559 (27 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ОКСИНИТРИДЫ ЦИРКОНИЯ -- ФЛЮОРИТОПОДОБНАЯ СТРУКТУРА Аннотация: The electronic energy structures of fluorite-like (F) zirconium dioxynitrides F-ZrO2-xNy in Zr-O-N systems were studied by the linear muffin-tin orbital--tight binding (LMTO-TB) ab initio band structure method. The electronic structures of defects (nitrogen atoms and anion vacancies) and their effect on the band structure of F-ZrO2 are discussed; defect clustering and probable reasons for structural ordering in the F-ZrO2-xNy phases are analyzed. Interatomic interaction indices are estimated in terms of Hiickel's semi-empirical band structure method. The cubic structure of zirconium dioxynitrides is stabilized by the formation of new bonding hybrid Zrd-Np states; the role of anion vacancies reduces to providing the optimal population of these states \\\\expert2\\NBO\\Journal of Structural Chemistry\\2000, V. 41, N 4, p.553-559.pdf |
Z 18 Zainullina, V. M. Quantum-chemical calculation of the electronic structure and ionic conductivity of lead hexaferrite with a magnetoplumbite structure / V. M. Zainullina, V. P. Zhukov, V. M. Zhukovskii // Journal of Structural Chemistry. - 2001. - Vol. 42, № 5. - P705-710 : il. - Bibliogr. : p. 710 (18 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): КВАНТОВО-ХИМИЧЕСКИЕ РАСЧЕТЫ -- ГЕКСАФЕРРИТ СВИНЦА -- ИОННАЯ ПРОВОДИМОСТЬ Аннотация: The ab initio linear muffin-tin orbital method in a tight binding approximation (LMTO-TB) and semiempirical extended Hückel theory (EHT) were used to study the electronic structure, chemical binding, and ion conductivity of hexaferrite PbFe12O19. The analysis of chemical bonds showed that Fe–O interactions play the dominant role in the chemical bonding in hexagonal ferrites, the covalent component of the Pb–O bond being insignificant. The metallic Fe–Fe bonds have been found. The predicted increased mobility of Pb2+ ions in the structure of magnetoplumbite agrees well with the experimental parameters of lead diffusion and ion–electron conductivity in PbFe12O19. The mechanism of migration of lead ions in the structure of the hexaferrite is discussed Полный текст |
E 43 Electronic structure and chemical bonding in monoclinic and cubic Li2-xHxTiO3 (0 / V. M. Zainullina, V. P. Zhukov, T. A. Denisova, L. G. Maksimova // Journal of Structural Chemistry. - 2003. - Vol. 44, № 2. - P180-186 : il. - Bibliogr. : p. 186 (14ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ЭЛЕКТРОННАЯ СТРУКТУРА -- ТИТАНАТ ЛИТИЯ -- РАСЧЕТЫ ЭЛЕКТРОННЫХ СПЕКТРОВ -- МЕТАТИТАНОВАЯ КИСЛОТА Аннотация: The linear "muffin-tin" orbitals method in a tight binding approximation and extended Huckel theory are used to study the electronic structure and chemical bonding of lithium titanate (Li2TiO3) and its protonated analogs (Li1:75H0:25TiO3 and H2TiO3). The e ect of protons on electron spectrum characteristics and bond strength are investigated for the monoclinic and cubic phases of lithium titanate. Phase stability is evaluated by cohesion energy calculations Полный текст |
Z 18 Zainullina, V. M. Defect Clusterization and Transport Properties of Oxide and Fluoride Ionic Conductors with Fluorite Structure: Quantum-Chemical Approach / V. M. Zainullina, V. P. Zhukov // Physics of the Solid State. - 2001. - Vol. 43, № 9. - P1686-1699 : il. - Bibliogr. : p. 1699 (67 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ТРАНСПОРТНЫЕ СВОЙСТВА -- ПРОВОДНИКИ ОКСИДНЫЕ -- ПРОВОДНИКИ ИОННЫЕ -- КЛАСТЕРИЗАЦИЯ Аннотация: Systematic studies of the effect of point defects on the electronic structure, chemical bond, and ionic conduction of classical ionic conductors MeF2 (Me = Ca, Sr, Ba, Pb), ZrO2–CaO, ZrO2–Y2O3, and delta-Bi2O3 are carried out using the nonempirical LMTO method in the tight-binding approximation and using Huckel’s semiempirical method. The energies of formation and interaction of anti-Frenkel defects are calculated. The effect of defect clusterization in these compounds is detected. This effect is responsible for the emergence of the superionic state and anomalous physicochemical properties of the given solid electrolytes. The nature of instability of the fluorite structure is studied, and methods of its stabilization are proposed. The mechanisms and energetics of ionic transport in oxide and fluoride conductors with fluorite structure are investigated Полный текст |