排序方式: 共有23条查询结果,搜索用时 15 毫秒
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V. T. Maslyuk E. Skordeva P. P. Puga D. Arsova V. Pamukchieva 《Physics of the Solid State》2004,46(8):1432-1437
Radiation-induced changes in the optical properties of chalcogenide glasses in the Ge-As-S system are investigated as a function of the concentration. Theoretical calculations are performed with due regard for possible constraints on the range of variation in the number of homobonds and heterobonds upon their switching in the structural network of chalcogenide glasses. The experimental data are obtained upon irradiation of GexAs40?xS60 thin films with fast electrons (6 MeV). The possible mechanism of structural transformations responsible for the specific features in the concentration dependence of the change in the band gap of chalcogenide glasses is discussed. 相似文献
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Using a combination of ab initio and semiempirical methods, adsorption problems on surfaces with large unit cells and low symmetry can still be studied. Here, a hybrid approach of density functional theory (DFT) and Hartree-Fock (HF) was used. As an example, we determined the geometry and the electronic properties of benzoic acid (BA), salicylic acid (SA) and para-salicylic acid (p-SA) adsorbed on MgSO(4).H(2)O (100), which are used as conditioner molecules for the electrostatic separation of minerals. Contrary to general expectations, these molecules are chemisorbed, with binding energies around 1.9 eV, forming bonds through the carboxylic O atom of the COOH groups in a nonplanar geometry, although the surface is a stoichiometric wide-band-gap insulator and the molecules stay intact. In contrast, a planar adsorption geometry turned out to be nonbonding. Bonding takes place by means of surface-molecule resonances due to the overlap of the valence band with molecular orbitals, assisted by a small charge-transfer molecule to the surface of around 0.15e. These combined interactions cause an intramolecular twist between the COOH group and the benzene ring. 相似文献
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Aristov VY Molodtsova OV Maslyuk VV Vyalikh DV Zhilin VM Ossipyan YA Bredow T Mertig I Knupfer M 《The Journal of chemical physics》2008,128(3):034703
The electronic structure of the organic semiconductor copper-phthalocyanine (CuPc) has been determined by a combination of conventional and resonant photoemission, near-edge x-ray absorption, as well as by the first-principles calculations. The experimentally obtained electronic valence band structure of CuPc is in very good agreement with the calculated density of states results, allowing the derivation of detailed site specific information. 相似文献
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V. V. Maslyuk V. Y. Aristov O. V. Molodtsova D. V. Vyalikh V. M. Zhilin Y. A. Ossipyan T. Bredow I. Mertig M. Knupfer 《Applied Physics A: Materials Science & Processing》2009,94(3):485-489
The electronic structure and morphology of organic semiconducting cobalt-phtalocyanine (CoPc) films in situ prepared on the
Au(001)-5×20 superstructure have been studied by a combination of experimental and theoretical work. The CoPc molecular film
was characterized by photoemission spectroscopy (PES, valence band and core-level). The experimental results were simulated
and have been explained in the framework of density functional theory (DFT) calculations. The C 1s and N 1s core level spectra were analyzed by taking into account the fact that both types of atoms have different nonequivalent positions
in the molecule. And finally, the experimentally obtained electronic valence band structure of CoPc is in very good agreement
with ab initio density of state results, allowing a detailed site-specific insight into the system. 相似文献
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Volodymyr V. Maslyuk Steven Achilles Ingrid Mertig 《Solid State Communications》2010,150(11-12):505-509
We present a theoretical study of the length dependence of both conductance and thermopower of organometallic vanadium-benzene molecules (V nBzn+1) sandwiched between magnetic Co(100) electrodes. We show that the molecules with n≥3 are efficient spin filters. Namely, we find that the zero bias conductance of the majority electrons is small and decays exponentially with increasing length of the molecule and is in the tunneling regime while the minority electrons show metallic conductance. We show furthermore that the thermopower strongly depends on the length of the molecules and can even change sign as a function of length and temperature. 相似文献
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A. Bolshakova E. Yu. Makido V. T. Maslyuk I. G. Megela T. A. Moskovets F. M. Shurygin 《Russian Physics Journal》2006,49(2):166-169
The results of experimental studies of electrophysical properties of heavily doped n-InSb whiskers exposed to electron irradiation (13 MeV, 300 K) are reported. The limiting electrophysical parameters and the problem
of the Fermi-level pinning in irradiated InSb are discussed.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 42–45, February, 2006. 相似文献