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1.
K. Hamada T. Wada C. Guet 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):359-368
Stability of highly charged metal clusters in the electric field of an external ion is investigated with the classical liquid
drop model. We study the optimum shape of the cluster which has a local minimum of the total energy, taking account of the
effects of the surface charge polarization on the Coulomb energy and the cluster deformation on the surface energy. We find
that the cluster deformation greatly affects the total energy of the system and that a cluster with a fissility larger than
some critical value 0.7-0.8 can become unstable against deformation. We investigate the local competition between the Coulomb
force and the surface tension at the cluster surface and show that the surface charge polarization which is induced by the
external electric field significantly affects the shape of the cluster and its stability.
Received 5 November 2002 / Received in final form 27 January 2003 Published online 11 March 2003
RID="a"
ID="a"e-mail: hamada@konan-u.ac.jp 相似文献
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Gangadhara S Craig D Ennis DA Hartog DJ Fiksel G Prager SC 《Physical review letters》2007,98(7):075001
The impurity ion temperature evolution has been measured during three types of impulsive reconnection events in the Madison Symmetric Torus reversed field pinch. During an edge reconnection event, the drop in stored magnetic energy is small and ion heating is observed to be limited to the outer half of the plasma. Conversely, during a global reconnection event the drop in stored magnetic energy is large, and significant heating is observed at all radii. For both kinds of events, the drop in magnetic energy is sufficient to explain the increase in ion thermal energy. However, not all types of reconnection lead to ion heating. During a core reconnection event, both the stored magnetic energy and impurity ion temperature remain constant. The results suggest that a drop in magnetic energy is required for ions to be heated during reconnection, and that when this occurs heating is localized near the reconnection layer. 相似文献
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运用分子动力学方法模拟了常温下金属钛中氦团簇的生长过程.从能量的角度考察了氦团簇的生长机理.研究发现,随着氦团簇的生长,在氦团簇周围逐渐形成位错环缺陷,氦团簇与氦原子的结合能有逐渐下降的趋势,当氦团簇生长到一定尺寸时会通过发射周围缺陷以使得结合能上升,从而增强了进一步吸收氦原子的能力.模拟还发现,随着氦团簇的继续生长,氦团簇的形状由原来的不规则结构逐渐变成了较为规则的棱柱形结构,在随后的生长过程中其生长仅在(001)平面进行,沿[001]轴的厚度几乎不变.
关键词:
氦团簇
缺陷发射
分子动力学模拟 相似文献
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Packets of capillary waves on the surface of a horizontal water layer generated at coalescence with a layer of microdroplets (with a characteristic diameter of 50–100 μm) of the dissipative structure “droplet cluster” have been detected by high-speed video recording and the schlieren method. The shortest experimentally observed waves have a length of about 130 μm and their phase velocity exceeds 1.8 m/s. It has been found that the coalescence of a single drop initiates a self-sustained wave process, which induces the coalescence of hundreds of droplets in a time shorter than 1 ms, which form a cluster. 相似文献
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The nonlinear problem of the expansion of a uniform spherical cluster, which consists of ions with a charge sufficient to
accelerate relativistic energies has been solved precisely. It has been shown that relativistic non-linearity is responsible
for the formation of an expanding shell-type structure. The space-time and energy characteristics of the relativistically
exploding cluster have been found. 相似文献
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《Nuclear Physics A》1998,634(3):267-283
Recent studies have shown that the characteristics of the entrance and exit channels through compact quasi-molecular shapes are compatible with the experimental data on fusion, fission and cluster radioactivity when the deformation energy is determined within a generalized liquid drop model. Analytic expressions allowing to calculate rapidly the main characteristics of this deformation path through necked shapes with quasi-spherical ends are presented now; namely formulas for the fusion and fission barrier heights, the fusion barrier radius, the symmetric fission barriers and the proximity energy. 相似文献
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N. Berrah D. Rolles Z. D. Pe?i? M. Hoener H. Zhang A. Aguilar R. C. Bilodeau E. Red J. D. Bozek E. Kukk R. Díez Mui?o F.J. García de Abajo 《The European physical journal. Special topics》2009,169(1):59-65
Inner-shell and valence-shell photoionization of
van-der-Waals Xe clusters have been measured using both
angle-resolved photoelectron spectroscopy and velocity map ion
imaging technique. Both techniques have been used to probe the
electronic properties and the fragmentation dynamics of clusters
as a function of photon energy and cluster size. In particular,
the evolution of the photoelectron angular distributions and
partial cross sections as a function of photon energy and cluster
size has revealed cluster size effects similar to the ones found
in solids. Our cluster angular distribution parameters have been
compared to the free atoms. In addition, the measurement of the
fragmentation dynamic of the clusters seems to be photon energy
dependent. 相似文献
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The energy absorption efficiency of high-intensity (~10^{16}W/cm^2) femtosecond laser pulses in a dense jet of large rare-gas clusters has been measured. Experimental results show that the energy absorption efficiency is strongly dependent on the cluster size and can be higher than 90%. The measurement of the ion energy indicates that the average ion energies of argon and xenon can be as high as 90 and 100keV, respectively. The dependence of the average energy of the ions on the cluster size is also measured. At comparatively low gas backing pressure, the average ion energies of argon and xenon increase with increasing gas backing pressure. The average ion energy of argon becomes saturated gradually with further increase of the gas backing pressure. For xenon, the average ion energy drops a little after the gas backing pressure exceeds 9 bar (3.2×10^5 atoms/cluster). The result showing the existence of a maximum average ion energy has been interpreted within the framework of the microplasma sphere model. 相似文献
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We propose a mean-field free energy approach to simulate multi- component fluids. The model has been validated in terms of
the Laplace equation of capillarity and dispersion relation of interfacial waves. Simulations of a ternary system shows that
the total free energy decreases and reaches a minimum after phase separation has occurred. Different drop shapes can be obtained
by adjusting the interaction strengths between individual components. These results demonstrate that both macroscopic free
energy and microscopic fluid-fluid interactions have been well described in our multicomponent model. 相似文献
12.
E. E. Zhurkin V. F. Kosmach A. S. Kolesnikov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2007,1(2):176-180
A computer simulation of the bombardment of the Cu (111) surface with CuN and AuN polyatomic clusters differing in size (N = 1, 6, and 13) with energies of 0.5 and 5 keV/atom has been performed in the framework of classical molecular dynamics. The spatial distribution of the implanted atoms, their ranges, and range fluctuations (straggling) depending on the size N and energy E/N of the incident cluster has been investigated. It has been shown that an increase in the mean range and range straggling is observed at a fixed energy per incident atom as the cluster size N increases. At the same time, the effect of an increase in the range (at a specified value of E/N) gradually disappears with increasing cluster energy, whereas the effect of an increase in straggling is retained. These tendencies qualitatively agree with the available experimental observations. It has been shown that the dominating contribution to the increase in the atom range of the implanted cluster is made by the so-called clearing-the-way effect, which is weakened with increasing the incident cluster energy. The effect of the range straggling increasing is significantly due to the presence of nonlinear “spike” effects at the bombarded target. 相似文献
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A. Audzijonis G. Gaigalas L.
igas A. Pauliukas R.
altauskas A. erkus D. Balnionis A. Kvedaravi
ius 《Journal of Electron Spectroscopy and Related Phenomena》2008,164(1-3):19-23
The valence band (VB) energy levels of BiSeI crystals have been calculated and compared to the X-ray photoelectron spectra of SbSI crystals. A molecular cluster consisting of 20 molecules of BiSeI has been used to calculate the total VB density of states by the density functional theory (DFT) method. The spectrum of total VB density of states of the (BiSeI)20 cluster weighted by atomic photoemission cross-sections has been compared with the experimental X-ray photoelectron VB spectrum of SbSI type crystals. The cluster model calculation has showed that the core level energy splitting depends on the difference of ionic charges of the same atoms at the edges of the (BiSeI)20 cluster. 相似文献
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研究了每核子能量为 2 6 0— 4 5 0keV的H+2,H+3,H+4 H+5和H+7团簇离子在金膜中的能损 .发现团簇离子中平均每个质子的能损大于相同速度的单质子能损 ,即能损比大于 1,且随团簇离子的大小和速度的增加而增加. The energy losses of cluster ions H+2,H+3,H+4 H+5 and H+7with energy of 260-450 keV/p in solid films have been measured. It has been found that the energy loss per proton in clusters is larger than that of single proton with the same velocity as clusters, that is, the energy ratio is larger than 1. Energy ratio increases with increasing the cluster size and velocity. 相似文献
15.
A dispersion equation is derived for the capillary oscillations of a charged drop of an ideal incompressible liquid travelling in an ideal incompressible ambient allowing for the energy lost via emission of electromagnetic radiation. The intensity of electromagnetic radiation emitted by a single drop and a storm cloud has been estimated. 相似文献
16.
J. Westergren S. Nordholm A. Rosén 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):81-97
The cooling of the metal cluster Pd13 in an atmosphere of rare gas has been studied by means of computer simulation. By simulation, the average energy transfer
in collisions between one cluster and one gas atom has been obtained. Emphasis has been placed on conditions when the temperatures
of the colliding species are almost equal. All modes of motion, inclusive the translation, must be considered in order to
obtain vanishing energy transfer at equilibrium. A simulation scheme is presented by which the energy transfer is zero to
the cluster when the gas and the cluster temperatures are equal. At equilibrium the energy transfer does however not vanish
for all impact parameters. In the collisions with Pd13, the cluster is heated by collisions with a small impact parameter but equally cooled by collisions with a large impact parameter.
Argon and krypton are found to cool Pd13 equally efficiently while neon and helium are less efficient cooling agents.
Received 28 September 2001 / Received in final form 8 August 2002 Published online 12 November 2002
RID="a"
ID="a"e-mail: JanW@phc.gu.se 相似文献
17.
The MACQM Calculation for the BInding Energy of the Equilateral Triangle Structure of H3^— Cluster 总被引:6,自引:0,他引:6
Considering that the equilateral triangle structure of H3^- cluster can be formed from the interaction of H^- with two hydrogen atoms,a modified arrangement channel quantum mechanics method has been used to calculate the total energy curve for this structure,The result shows that the cureve has a minimal energy-1.6672 a.u.at an internuclear distance of 1.77a0,so its dissociation energy(binding energy)is D(H^- H H)=0.1395,a.u.This means that the cluster H3^- may be formed in an equilateral triangle structure with a bond length of 1.77α0. 相似文献
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使用可视化图形用户界面程序GaussView给出了Cu6团簇所有可能存在的结构, 用量化计算软件Gaussian03的B3LYP杂化密度泛函和SDD基组对所给结构进行优化, 最终得到了8种Cu6团簇的异构体。 对所得异构体的结合能和结构进行了分析, 发现结合能和实验值以及理论值符合得很好, 在结构方面其最稳定的是平面三角形结构。 在8种异构中有正五边形等3种结构是首次模拟得到的, 所得结果为以后的理论和实验工作提供了参考。 The possible structure of Cu6 cluster has been given with the GaussView that is a graphical user interface software. The structure optimization was performed on the B3LYP functional and SDD basic set of the quantum computational software of Gaussian03. And eight isomers of Cu6 cluster were calculated. The binding energy and the structure of eight isomers have been investigated in detail. The result showed that the value of the binding energy was in reasonable agreement with available experimental data, as well as with other theoretical results, and the most stable structure was the triangle of plane. Three new isomers of the Cu6 cluster have been got in our work, which would be the valuable data for the further theoretical and experimental study. 相似文献