Труды сотрудников института физики

/ P. V. Avramov [et al.] // J. Appl. Phys. - 2008. - Vol. 104, Is. 5. - Ст. 54305, DOI 10.1063/1.2973464. - Cited References: 22. - This work was, in part, partially supported by a Core Research for Evolutional Science and Technology (CREST) grant in the area of high performance computing for multi-scale and multiphysics phenomena from the Japan Science and Technology Agency (JST) as well as by the Russian Fund of Basic Researches (Grant No. 05-02-17443) (L.A.C.). One of the authors (P.V.A.) acknowledges the encouragement of Dr. Keiji Morokuma, Research Leader at Fukui Institute. The geometry of all presented structures was visualized by ChemCraft software. SUP23/SUP L.A.C. acknowledges I. V. Stankevich for help and fruitful discussions. P.B.S. is grateful to the Joint Supercomputer Center of the Russian Academy of Sciences for access to a cluster computer for quantum-chemical calculations. . - ISSN 0021-8979РУБ Physics, Applied

Аннотация: Motivated by the experimental discovery of branched silicon nanowires, we performed theoretical electronic structure calculations of icosahedral silicon quantum dots embedded into pentagonal silicon nanowires. Using the semiempirical method, we studied the quantum confinement effect in the fully optimized embedded structures. It was found that (a) the band gaps of the embedded structures are closely related to the linear sizes of the longest constituting part rather than to the total linear dimension and (b) the discovered atypical quantum confinement with a plateau and a maximum can be attributed to the substantial interactions of near Fermi level electronic states of the quantum dots and nanowire segments. (c) 2008 American Institute of Physics.

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Держатели документа:
[Avramov, Pavel V.] Kyoto Univ, Fukui Inst Fundamental Chem, Kyoto 6068103, Japan
[Fedorov, Dmitri G.] Natl Inst Adv Ind Sci & Technol, Res Inst Computat Sci, Tsukuba, Ibaraki 3058568, Japan
[Sorokin, Pavel B.
Ovchinnikov, Sergei G.] LV Kirensky Inst Phys SB RAS, Krasnoyarsk 660036, Russia
[Sorokin, Pavel B.
Ovchinnikov, Sergei G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Sorokin, Pavel B.
Chernozatonskii, Leonid A.] RAS, NM Emanuel Inst Biochem Phys, Moscow 119334, Russia
ИФ СО РАН
Fukui Institute for Fundamental Chemistry, Kyoto University, 34-3 Takano Nishihiraki, Sakyo, Kyoto 606-8103, Japan
Research Institute for Computational Science, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8568, Japan
L.V. Kirensky Institute of Physics, SB, RAS, 660036 Krasnoyarsk, Russian Federation
Siberian Federal University, 79 Svobodny Av., 660041 Krasnoyarsk, Russian Federation
N.M. Emanuel Institute of Biochemical Physics, RAS, 119334 Moscow, Russian Federation

Доп.точки доступа:
Avramov, P. V.; Аврамов, Павел Вениаминович; Fedorov, D. G.; Sorokin, P. B.; Chernozatonskii, L. A.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич

/ A. S. Fedorov, M. V. Serzhantova, A. A. Kuzubov // J. Exp. Theor. Phys. - 2008. - Vol. 107, Is. 1. - P. 126-132, DOI 10.1134/S1063776108070121. - Cited References: 15. - This study was supported financially by the Russian Foundation for Basic Research ( project no. 06-02-16132). The authors are also grateful to the Institute of Computer Modeling of the Siberian Branch of the Russian Academy of Science for providing a cluster computer on which all quantum-chemistry calculations were performed. . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: The stability of magnesium hydride (MgH (x) ) nanoparticles (x = 0.5,...,2) is investigated using ab initio calculations. It is shown that for a nanoparticle diameter of D similar to 5 nm, the internal pressure becomes lower than 3 kbar; for this reason, the structure of hydride nanoparticles coincides with the structure of this hydride in crystalline form. It is found that the phase of partly saturated MgH (x) hydrides (x < 2) must decompose into the phase of pure hcp magnesium and the alpha phase of MgH(2). The frequencies of jumps of hydrogen atoms within the hcp phase of magnesium and in the alpha phase of MgH(2) are calculated; it is shown that slow diffusion of hydrogen in magnesium is due to the large height of potential barriers for motion of hydrogen within MgH(2). To attain high diffusion rates, the structures of Mg(53)Sc and Mg(53)Ti crystals and their hydrides are calculated. It is found that the frequency of jumps of H atoms in Mg(53)ScH(108) near the Sc atoms does not noticeably change as compared to the frequency of jumps in the alpha phase of MgH(2), while the frequency of jumps in Mg(53)TiH(108) near Ti atoms is higher by approximately a factor of 2.5 x 10(6). This means that diffusion in manganese hydride with small admixtures of titanium atoms must be considerably eased. Chemical dissociation of hydrogen molecules on the (0001) surface of hcp magnesium, on the given surface with adjoined individual Ti atoms, and on the surface of a one-layer titanium cluster on the given surface of magnesium is investigated. It is found that dissociation of hydrogen at solitary titanium atoms, as well as on the surface of a Ti cluster, is facilitated to a considerable extent as compared to pure magnesium. This should also sharply increase the hydrogen adsorption rate in magnesium nanoparticles.

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Держатели документа:
[Fedorov, A. S.
Kuzubov, A. A.] Russian Acad Sci, Siberian Branch, Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
[Serzhantova, M. V.
Kuzubov, A. A.] Siberian Fed Univ, Krasnoyarsk 660028, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation
Siberian Federal University, Akademgorodok, Krasnoyarsk, 660028, Russian Federation

Доп.точки доступа:
Serzhantova, M. V.; Kuzubov, A. A.; Кузубов, Александр Александрович; Федоров, Александр Семенович