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581.
Rousseau R De Renzi V Mazzarello R Marchetto D Biagi R Scandolo S del Pennino U 《The journal of physical chemistry. B》2006,110(22):10862-10872
We have isolated at T < 150 K a weakly adsorbed dimethyl disulfide (DMDS) layer on Au(111) and studied how the vibrational states, S core hole level shifts, valence band photoemission, and work function measurements evolve upon transforming this system into chemisorbed methylthiolate (MT) self-assembled monolayers (SAM) by heating above 200 K. By combining these observations with detailed theoretical electronic structure simulations, at the density functional level, we have been able to obtain a detailed picture of the electronic interactions at the interface between Au and adsorbed thiolates and disulfides. All of our measurements may be interpreted with a simple model where MT is bound to the Au surface with negligible charge transfer. Interfacial dipoles arising from Pauli repulsion between molecule and metal surface electrons are present for the weakly adsorbed DMDS layer but not for the chemisorbed species. Instead, for the chemisorbed species, interfacial dipoles are exclusively controlled by the molecular dipole, its interaction with the dipoles on neighboring molecules, and its orientation to the surface. The ramifications of these results for alignment of molecular levels and interfacial properties of this class of materials are discussed. 相似文献
582.
Yao K Zhang ZY Liang XL Chen Q Peng LM Yu Y 《The journal of physical chemistry. B》2006,110(43):21408-21411
Field effect transistors have been fabricated using Bi2S3 nanowires. Whether the contact is ohmic or non-ohmic, the current of Bi2S3 nanowires was found to increase remarkably in H2 compared to that in a vacuum. Carrier density and mobility within the nanowires and the contact barriers between the nanowires and the electrodes have been extracted using field effect and two-probe current-voltage curves. It was found that H2 enhances electronic mobility and carrier density within the nanowires dramatically. The effect of H2 on the contact barriers was observed to be negligible compared to the other two effects. 相似文献
583.
584.
Jérôme Le Rousseau 《Journal d'Analyse Mathématique》2009,109(1):81-162
We consider the first-order Cauchy problem
$
\begin{gathered}
\partial _z u + a(z,x,D_x )u = 0,0 < z \leqslant Z, \hfill \\
u|_{z = 0} = u_0 , \hfill \\
\end{gathered}
$
\begin{gathered}
\partial _z u + a(z,x,D_x )u = 0,0 < z \leqslant Z, \hfill \\
u|_{z = 0} = u_0 , \hfill \\
\end{gathered}
相似文献
585.
Changes in domain wall resistance under radio-frequency (RF) irradiation are experimentally studied for transverse walls. An original experimental technique is applied to the measurement in a permalloy nano-stripe with a notch, where the walls are found to provide a largely enhanced resistive response as compared to saturated domains. Their susceptibility is found to be an order of magnitude larger than that of the domains in a frequency range between 5 and 20 GHz. We argue that the RF fields induce an internal distortion of the magnetization profile that depends on the shape of the domain wall. 相似文献
586.
M. Mortier J. Y. Gesland M. Rousseau M. A. Pimenta L. O. Ladeira J. C. Machado Da Silva G. A. Barbosa 《Journal of Raman spectroscopy : JRS》1991,22(7):393-396
Single crystals of the fluoride compound KY3F10 (Oh5) were studied by Raman scattering from 40 to 950 K. Group theory analysis predicts 3A1g + 4Eg + 6F2g Raman-active modes, but the experimental spectra show two F2g modes missing. Over the whole temperature range the frequency shifts are negligible whereas the line widths show a strong increase with temperature. Both reversible and irreversible line width behaviour are exhibited for different temperature runs, indicating a complex microscopic phenomenon underlying the creation of defects responsible for these line widths and their interaction with the different phonon modes. An approximate activation energy for defect creation of ΔE ≈︁ 0.3 eV can be obtained from the temperature behaviour of the line widths. This activation energy may be connected with the high-temperature ionic conduction mentioned previously for this crystal. 相似文献
587.
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