排序方式: 共有22条查询结果,搜索用时 781 毫秒
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Amy F Chan CK Zhao W Hyung J Ono M Sueyoshi T Kera S Nesher G Salomon A Segev L Seitz O Shpaisman H Schöll A Haeming M Böcking T Cahen D Kronik L Ueno N Umbach E Kahn A 《The journal of physical chemistry. B》2006,110(43):21826-21832
Monolayers of alkyl chains, attached through direct Si-C bonds to Si(111), via phosphonates to GaAs(100) surfaces, or deposited as alkyl-silane monolayers on SiO2, are investigated by ultraviolet and inverse photoemission spectroscopy and X-ray absorption spectroscopy. Exposure to ultraviolet radiation from a He discharge lamp, or to a beam of energetic electrons, leads to significant damage, presumably associated with radiation- or electron-induced H-abstraction leading to carbon-carbon double-bond formation in the alkyl monolayer. The damage results in an overall distortion of the valence spectrum, in the appearance of (occupied) states above the highest occupied molecular orbital of the alkyl molecule, and in a characteristic (unoccupied state) pi resonance at the edge of the carbon absorption peak. These distortions present a serious challenge for the interpretation of the electronic structure of the monolayer system. We show that extrapolation to zero damage at short exposure times eliminates extrinsic features and allows a meaningful extraction of the density of state of the pristine monolayer from spectroscopy measurements. 相似文献
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L. Kronik R. Fromherz E. Ko G. Ganteför J. R. Chelikowsky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):33-36
We compare experimentally measured and
ab initio computed
photoelectron spectra of negatively charged deuterated silicon
clusters (
, 4m10, 0n2) produced in a plasma environment.
Based on this comparison, we discuss the kinetics and
thermodynamics of the cluster formation and the effect of
deuterium on the geometrical and electronic structure of the
clusters. 相似文献
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The electronic structure and magnetic properties of Mn-doped Ge, GaAs, and ZnSe nanocrystals are investigated using real space ab initio pseudopotentials constructed within the local spin-density approximation. The ferromagnetic and half-metallicity trends found in the bulk are preserved in the nanocrystals. However, the Mn-related impurity states become much deeper in energy with decreasing nanocrystalline size, causing the ferromagnetic stabilization to be dominated by double exchange via localized holes rather than by a Zener-like mechanism. 相似文献
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Li Y Calder S Yaffe O Cahen D Haick H Kronik L Zuilhof H 《Langmuir : the ACS journal of surfaces and colloids》2012,28(26):9920-9929
Since the first report of Si-C bound organic monolayers on oxide-free Si almost two decades ago, a substantial amount of research has focused on studying the fundamental mechanical and electronic properties of these Si/molecule surfaces and interfaces. This feature article covers three closely related topics, including recent advances in achieving high-density organic monolayers (i.e., atomic coverage >55%) on oxide-free Si(111) substrates, an overview of progress in the fundamental understanding of the energetics and electronic properties of hybrid Si/molecule systems, and a brief summary of recent examples of subsequent functionalization on these high-density monolayers, which can significantly expand the range of applicability. Taken together, these topics provide an overview of the present status of this active area of research. 相似文献
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We present a two-part systematic density functional theory (DFT) study of the electronic structure of selected transition
metal phthalocyanines. We use a semi-local generalized gradient approximation (GGA) functional, as well as several hybrid
exchange-correlation functionals, and compare the results to experimental photoemission data. Here, we study the intermediate
spin systems MnPc and FePc. We show that DFT calculations of these systems are extremely sensitive to the choice of functional
and basis set with respect to the obtained electronic configuration and to symmetry breaking. Interestingly, all simulated
spectra are in good agreement with experiment despite the differences in the underlying electronic configurations. 相似文献
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The electrical response of molecular chains is dramatically overestimated by local and semilocal density functionals. We show that Kohn-Sham density-functional theory yields accurate linear and nonlinear polarizabilities when the exact exchange energy is employed together with the corresponding exact Kohn-Sham potential upsilonx(r). We further show that approximations to upsilonx(r) that are very accurate for the ground-state energy can nevertheless fail badly for the response because of potential barriers that have little effect on the ground-state energy but strongly affect the electron mobility. 相似文献