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排序方式: 共有282条查询结果,搜索用时 750 毫秒
1.
Q. Sun Q. Wang X.G. Gong V. Kumar Y. Kawazoe 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(1):77-81
We report results of the atomic and electronic structures of Al7C cluster using ab initio molecular dynamics with ultrasoft pseudopotentials and generalized gradient approximation. The lowest energy structure is
found to be the one in which carbon atom occupies an interstitial position in Al7 cluster. The electronic structure shows that the recent observation [Chem. Phys. Lett. 316, 31 (2000)] of magic behavior of Al7C- cluster is due to a large highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) gap which makes Al7C- chemically inert. These results have further led us to the finding of a new neutral magic cluster Al7N which has the same number of valence electrons as in Al7C- and a large HOMO-LUMO gap of 1.99 eV. Further, calculations have been carried out on (Al7N)2 to study interaction between magic clusters.
Received 28 July 2001 相似文献
2.
P. Adamson 《Optics & Laser Technology》2002,34(7):561-568
The differential reflection characteristics for ultrathin inhomogeneous dielectric film on absorbing substrate are investigated in the long-wavelength approximation. The obtained first-order expressions for differential reflectivity and changes in the ellipsometric angles caused by ultrathin layer are of immediate interest to the solution of the inverse problem. The method to determine the averaged values (not the realistic profile) of refractive index for inhomogeneous nanometric films are shown. The novel possibilities for determining the dielectric constant and thickness of nanoscale homogeneous films by the differential ellipsometric and reflectivity measurements are developed, and a simple method to estimate whether the nanometric film is homogeneous or not is also discussed. 相似文献
3.
N. Nishi J. Nishijo K. Judai C. Okabe O. Oishi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):287-290
UV photoexcitation of (t-butylethynyl copper)24
cluster films induces segregation of the crystals into metallic and organic
phases and leads to evolve the metallic sheets sandwiched by organic
polymers. The growth of the metallic crystals in the plane of the
photo-electromagnetic field is attributed due to plasmon-plasmon interaction
among nanoparticles embedded in dielectric polymer matrices. The surface
enhanced photochemical reaction of residual cluster molecules on the photon
incident direction is expected to take an important role for joining the
metal particles to produce a metallic sheet. We can apply this phenomenon
for photolithographic copper pattern generation on a flexible base plate. 相似文献
4.
Qingrong Zheng Gang Su Jian Wang Hong Guo 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,25(2):233-238
We report a theoretical analysis of the phonon thermal conductance, κ(T), for single wall carbon nanotubes (SWCN). In a range of low temperatues up to 100 K, κ(T) of perfect SWCN is found to increase with temperature, approximately, in a parabolic fashion. This is qualitatively consistent
with recent experimental measurements where the tube-tube interactions are negligibly weak. When the carbon-carbon bond length
is slightly varied, κ(T) is found to be qualitatively unaltered which implies that the anharmonic effect does not change the qualitative behavior
of κ(T).
Received 12 June 2001 相似文献
5.
C. Bréchignac Ph. Cahuzac F. Carlier C. Colliex M. de Frutos N. Kébaïli J. Le Roux A. Masson B. Yoon 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):265-268
We studied shape relaxation of nano-fractal islands,
during annealing, after their growth from antimony cluster
deposition on graphite surface. Annealing at
180°C shows evidence of an increase
of the fractal branch width with time followed by branch
fragmentation, without changing the fractal dimension. The time
evolution of the width of the arm suggests the surface
self-diffusion mechanism as the main relaxation process. With
Monte Carlo simulations, we confirmed the observed behavior.
Comparison is done with our previous results on fragmentation of
nano-fractal silver islands when impurity added to the incident
cluster promotes rapid fragmentation by surface self-diffusion
enhancement [1]. 相似文献
6.
S. Sasa A. Nakashima Y. Nakajima M. Inoue 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):224
We fabricated nanoscale open-dot structures in an InAs surface inversion layer using an atomic-force-microscope oxidation process. Due to its superior nanofabrication capability, small open-dot structures with the feature size ranging between 100 and 300 nm were successfully fabricated. The magnetoresistance signal measured at 4.2 K showed reproducible fluctuations and a periodic oscillation component that varies in both amplitude and periodicity depending on the dot size. We show that the period of the oscillations corresponds to that of the Aharonov–Bohm effect and propose that the possible mechanism for the oscillations is due to the formation of a one-dimensional electron channel enclosing the open-dot structure as a result of the electron transfer from the InAs oxide to InAs. 相似文献
7.
Adam Bange Jian Tu Xiaoshan Zhu Chong Ahn H. Brian Halsall William R. Heineman 《Electroanalysis》2007,19(21):2202-2207
A microbead based sandwich immunoassay for MS2 bacteriophage was developed using an interdigitated array (IDA) electrode with nanoscale dimensions (220 nm electrode width, 620 nm gap). The IDA was fabricated using an electron beam lithographic lift‐off technique. After an antibody‐assisted capture of MS2 using paramagnetic microbeads, a β‐galactosidase labeled secondary antibody was used to convert p‐aminophenyl‐β‐D ‐galactopyranoside (PAPG) into the redox active p‐aminophenol (PAP). Amperometric detection of PAP with IDA electrodes at +300 and ?200 mV vs. a Ag/AgCl reference electrode was used to measure the result, detecting MS2 concentrations as low as 10 ng/mL. 相似文献
8.
Pd nanoparticles have been successfully supported on nanoscale metal-organic frameworks (NMOFs) by using a simple and effective microwave-assisted impregnation process. The resulting composite, representing as a highly active NMOFs supported metal nanoparticles catalyst for the Suzuki cross-coupling reaction between aryl/heteroaryl halides and arylboronic acids, is well characterized, and its high activity and good recyclability are discussed in details. It reveals that, compared to the corresponding bulk MOFs and conventional active carbon materials, nanoscale MOFs as novel support materials for heterogeneous catalysts can exhibit superior performance in the catalytic reactions. 相似文献
9.
J. Wang J. Zhao L. Ma G. Wang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(2):289-294
The stuffed fullerene structures of medium-sized SiN
(
) clusters have been systemically studied
using the all-electron density functional theory with gradient correction.
For each cluster size, fullerene cages with different topologies and filled
by different number of atoms were constructed and optimized to find the
lowest-energy structure. The core atoms filled in the fullerene cages tend
to form cage-like structures that resemble structural character of bulk
diamond fragments. The size-dependent physical properties such as binding
energies, electronic gaps, and ionization potentials have been discussed.
Si45 exhibits relatively higher stability that can be associated with
the low chemical reactivity observed by experiment. 相似文献
10.
I. Popov T. Kunze S. Gemming G. Seifert 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(3):439-446
The preferred adsorption sites and the propensity for a self-organised growth of the molybdenum sulfide cluster Mo6S8 on the Au(111) surface are investigated by density-functional band-structure calculations with pseudopotentials and a plane
wave basis set. The quasi-cubic cluster preferentially adsorbs via a face and remains structurally intact.
It experiences a strong, mostly non-ionic attraction to the surface
at several quasi-isoenergetic adsorption positions. A scan of the potential energy surface exhibits only small barriers between
adjacent strong adsorption sites. Hence, the cluster may move in a potential well with degenerate local energy minima at room
temperature. The analysis of the electronic structure reveals a negligible
electron transfer and S-Au hybridised states, which indicate that the cluster-surface
interaction is dominated by S-Au bonds, with minor contributions from
the Mo atom in the surface vicinity. All results indicate that Mo6S8 clusters
on the Au(111) surface can undergo a template-mediated self-assembly to an ordered inorganic monolayer, which is still redox
active and may be employed as surface-active agent in the integration of noble metal and ionic or biological components within
nano-devices.
Therefore, a classical potential model was developed on the basis of the DFT data,
which allows to study larger cluster assemblies on the Au(111). 相似文献