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21.
Jaspreet Sandhu Amit Kumar Singh Chauhan Govind 《Journal of nanoparticle research》2011,13(8):3503-3509
The room temperature growth of gallium atoms on the highly oriented pyrolytic graphite (HOPG) surface has been performed.
The gallium atoms were deposited by thermal evaporation method in an ultra high vacuum system at a base pressure 5 × 10−10 torr. The X-ray photo electron spectroscopy (XPS) studies had been performed to confirm the presence of gallium atoms on
HOPG surface. Scanning tunneling spectroscopy (STM) technique was employed to study the surface morphology of the clean HOPG
surface and gallium covered HOPG surfaces which recognize the formation of gallium induced nanostructures. The deconvoluted
XPS core level spectra of C (1s) and Ga (3d) demonstrate the possible interaction between substrate and the adsorbate atoms.
The STM analysis revealed that the gallium deposition on HOPG led to significant change in the surface morphology. It was
observed that the Ga atoms adsorbed as layer structure on HOPG surface for low coverage while quasi one-dimensional chain
like nanostructure (1 ± 0.2 nm) has been formed for higher Ga coverage. The nanostructured surfaces induced by Ga deposition
are found to be stable and could be used as a template for the growth of metallic nanostructures. 相似文献
22.
Getmanenko YA Risko C Tongwa P Kim EG Li H Sandhu B Timofeeva T Brédas JL Marder SR 《The Journal of organic chemistry》2011,76(8):2660-2671
A series of trialkylsilyl-substituted 2,2'-dithiophene, 4,4'-di-n-hexyl-2,2'-dithiophene, 5,5'-dithiazole, and 2,2'-diselenophene with carbonyl (2a-d) and α-dicarbonyl bridges (3a-d) were prepared from readily available dihalides, using double lithiation followed by trapping with N,N-dimethylcarbamoyl chloride or diethyl oxalate (or N,N-dimethylpiperazine-2,3-dione), respectively. Cyclic voltammetry reveals that the first half-wave reduction potentials for this series of compounds span a wide range, from -1.87 to -0.97 V vs the ferrocene/ferrocenium couple at 0 V (0.1 M (n)Bu(4)NPF(6) in THF). A significant increase of the first half-wave reduction potential (by 0.50-0.67 V) was observed on substitution of the monocarbonyl bridge with α-dicarbonyl. Adiabatic electron affinity (AEA, gas phase) trends determined via density functional theory (DFT) calculations are in good agreement with the electrochemical reduction potentials. UV-vis absorption spectra across the series show a weak absorption band in the visible range, corresponding to the HOMO→LUMO transition within a one-electron picture, followed by a more intense, high-energy transition(s). Single-crystal X-ray structural analyses reveal molecular packing features that balance the interplay of the presence of the bulky substituents, intermolecular π-stacking interactions, and S···O intermolecular contacts, all of which affect the DFT-evaluated intermolecular electronic couplings and effective charge-carrier masses for the crystals of the tricyclic cores. 相似文献
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Molar extinction coefficients of some carbohydrates viz. l-arabinose (C5H10O5), d-glucose (C6H12O6), d-mannose (C6H12O6), d-galactose (C6H12O6), d(-) fructose (C6H12O6) and maltose (C12H24O12) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a
narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter
polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying
within experimental uncertainty. Within concentration ranges studied, Beer-Lambert law is obeyed very well. 相似文献
26.
The diorganotin(IV) and triorganotin(IV) derivatives R2SnA (R = Me, n-Pr, n-Bu, n-Oct) and (R3Sn)2A [R = Me, Ph, cyclohexyl (Cyh); A = an anion of diphenic acid] have been prepared and characterized by elemental analysis, IR, 1H and 13C NMR spectroscopies. Tetrahedral tin forms a part of a diphenate cyclic ring in the diorganotin complexes with unidentate carboxylates, which have further been used for the synthesis of cyclic acid anhydrides. The soluble dinuclear triorganotin complexes (Me, Ph) possess symmetrically bonded carboxylates while the less soluble compound (Cyh3Sn)2A has two asymmetrically bonded carboxylates. All have a trigonal bipyramidal structure with R3Sn units remote from each other. 相似文献
27.
By monitoring the relative concentrations of mercury 3P0 atoms using absorption photometry, absolute rate constants have been measured for the excimer-forming reaction Hg (3P0) + Hg + N2 → Hg2* + N2 and for the quenching of Hg (3P0) atoms by ethane, propane, deuterated propanes, and nitrous oxide. 相似文献
28.
Measurements of the differential cross sections for the elastic scattering of 30.5 MeV protons by 24Mg and for the inelastic scattering to the 1.37, sum of 4.12 and 4.23, 5.22 and 6.0 MeV states are reported. Optical model fits to the elastic data, a distorted wave calculation for the first excited state, and coupled channel calculations are also presented. 相似文献
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The thermal decompositions of metal(II) hexacyanoferrates(II) (Co, Ni and Zn) were studied in air with Mössbauer, infrared, thermal analysis and magnetic susceptibility techniques. Dehydration is almost complete at 200° and decomposition starts at 250° in the cases of cobalt and nickel hexacyanoferrates(II), and at 300° for zinc hexacyanoferrates (II). Finally, ferrites are formed as decomposition products. 相似文献