共查询到20条相似文献,搜索用时 15 毫秒
1.
In this paper, the quark-antiquark one gluon exchange potential corresponding to the annihilation channels is calculated to the order of p2/m2 by means of Fierz reordering transformation. The nucleon-antinucleon effective potential obtained from one gluon exchange potential has a strong attraction at a short distance as expected in the meson-exchange theory. 相似文献
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In this paper, first of all, we proved if the ideal Bose gas with a finite volume and number of particles has a non-degenerate single-particle energy level εn, the chemical potential μ can take the value μn=εn and there is a phase transition temperature Tp,n, where n=0,1,2… Taking ε0≤εn<εn+1, then Tp,0≥Tp,n>Tp,n+1. When the temperature T>Tp,n or T≤Tp,n+1, μ≠εn and the most probable occupation number Nn=0. In the temperature interval Tp,n≥ T>Tp,n+1,μ=εn and 0≤Nn=N-ΣjNj<~supNn, where Nj is the most probable occupation number in the degenerate level j. Thus, if the finite ideal Bose gas has some non-degenerate single-particle levels, there exists a characteristic temperature Tp=Tp,0. The chemical potential μ is quantized when T≤Tp, and this leads to the creation of a macroscopic quantum state (pure state) or Bose-Einstein condensation phase. Tp=Tp,0 is a first-order phase transition point, Tp,n≠0 is a zero-order phase transition point. Next, we obtained a new expression of the most probable distribution of the finite ideal Bose gas. In this expression Nj is directly proportional to gj-1, where gj and Nj are, respectively, the degeneracy and the most probable occupation number in the degenerate level j. This property agrees with what chemical potential can be quantized if there is a non-degenerate level for the finite ideal Bose gas. Finally, using this expression, we defined a micro-partition function M, obtained the statistical expressions of some thermodynamical quantities. 相似文献
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C2分子的分析势能函数与垂直电离势 总被引:3,自引:3,他引:0
用abinitio计算方法和实验光谱数据分别导出C2分子基态X1Σ+g和激发态d3Πg的Murel-Sorbie函数,同时用QCISD/6-311G方法优化出C-2、C+2、C2+2分子离子基态的平衡核间距,算出C2分子的垂直电离势,计算数据与实验光谱数据进行了比较。 相似文献
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MM-4中电位和分布实验 总被引:1,自引:1,他引:0
本文描述了用静电探针测量探针悬浮电位的方法,给出了MM-4电位分布的实验结果。结果表明,轴向电位分布不对称;在等离子体中沿轴向和径向存在双离子位阱。在离子能谱测量中观察到双离子温度。产生这样电位分布的机制,归于会切系统中的斯托沫区和电子枪的不同工作方式。测量的等离子体电位为-200——300V。 相似文献
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本文从与真空接触的存在二支声子的半无限极性晶体表面附近极化子的哈密顿算符入手,应用二支模型理论,分别对GaAs和ZnO两种材料计算了内表面电子的量子像势及其极化子的有效势。计算结果表明:当Z很小时,经典像势和半经典有效势分别与量子像势和量子有效势相差较大;当Z很大时,经典像势和半经典有效势分别是量子像势和量子有效势的一个很好的近似。 相似文献
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用相对论有效原子实势 (RECP)和密度泛函 (B3LYP SDD)方法研究了UH ,UH2 基态和低激发态的结构和势能函数 ,导出了分子的光谱数据 .结果表明 ,UH和UH2 的基电子状态分别为X4 Π和X3A2 ,离解能分别为 2 .886eV和5 .2 4 9eV ,UH2 具有C2v对称性 ,得到了UH和UH2 的几个不同的低激发态的结构与光谱数据 .应用多体项展式理论以及数字拟合方法 ,计算得到了UH分子和基态UH2 三原子分子的分析势能函数 ,该函数正确反映了UH和UH2分子的结构特征 ,可用于研究UHH的微观反应动力学 . 相似文献
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用相对论有效原子实势 (RECP)和密度泛函 (B3LYP)方法对Pun(n =2 ,3)体系的结构进行了优化 ,得到了Pu2 和Pu3分子的几何构型分别为D∞h,D3h,其基态分别为 13和 19重态 .在B3LYP RECP水平上得到Pu2 分子的光谱常数ωe=5 2 .3845cm- 1 ,ωe χe=0 .0 2 0 1cm- 1 和Pu3分子的谐振频率 (ν1 =5 6 .90 0 7cm- 1 ,ν2 =5 7.1816cm- 1 ,ν3=6 4 0 785cm- 1 )等性质 ,并通过正规方程组和多体展式理论 ,得到了Pu2 ,Pu3的分析势能函数 . 相似文献
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本文给出了发射探针和电容探针测量等离子体电位的实验和方法。发射探针采用直流功率加热,并在较强电子发射条件下运行(I_(e0)/I_(e0)>1)。电容探针表面二次电子发射系数δ≥1。本文对发射探针的电子发射性能、工作电流、电容探针的输入、输出电压关系进行了标定实验。得到了电容探针的校准系数分别为3×10(-3)、5×10(-4)。实验给出了MM-4会切中心等离子体电位V_(p4)=-82±9-122±12V;MM-4U东、西会切中心等离子体电位分别为V_(P4u1)=-52.9±3.2V,V_(P4u2)=-62±3.2V。 相似文献
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Shi-shu WU 《理论物理通讯》1983,2(2):1059-1063
The principle of maximum overlap is applied to the derivation of optimal single particle (sp) wave functions for a many-fermion system under the proposition that the ground state correlation should be taken into account rigorously. If the sp potential Uαβ is defined in terms of the mass operator Mαβ(u) by uαβ=Mαβ(εβ), it is shown that the eigenfunctions of the sp Hamiltonian hαβ=tαβ+uαβ automatically fulfill the requirements of the above principle. 相似文献
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利用Guassian94程序和QCISD/6-311++G方法得到He-HF和He-FH两种线性平衡结构,计算出了这两种弱结合分子的结构参数、离解能和二阶力常数。在此基础上,利用多体项展式方法民出He-HF(X^1Σ^+)体系的分析势能函数,得到的势能面准确地再现了He-HF和He-FH两种线性结构。 相似文献
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Ar—HF体系的结构,性质和分析势能函数 总被引:2,自引:1,他引:1
利用Gaussian92程序和CID/6—311G*方法优化得到ArHF和ArFH两种线性平衡结构,计算出了这两种弱结合分子的结构参数和离解能,并使用该程序和MP2/6—311G*方法计算得到它们的力常数。在此基础上,利用多体项展式方法导出ArHF(X1Σ+)体系的分析势能函数,得到的势能面正确地再现了ArHF和ArFH两种线性结构,预测出ArHF有Cs结构存在。 相似文献
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In the framework of fixed-scatterer field theory,we construct the second order iso-elastic microscopic pion-nucleus optical potential by including two nucleon correlation.The double charge exchange reactions to the double isobaric analog state are calculated by using our theoretical optical potential.For the incident pion energies ranging between 0 and 300MeV,the s and p wave components are included in the πN amplitude. 相似文献
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The finite temperature effective potential in SUSY Weinberg-Salam model, proposed by Sohnius, is calculated. The temperature of the phase transition is found approximately. The scale of this temperature is of the order of hiqqs mass, it is the same as that in standard model. There is no influence on the phase transition from the Slavnov term. The cosmological inflationt SU(2)×U(1)epoch in such a model is estimated. 相似文献
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In this presentation, the quantization and renormalization of the Yang-Mills field theory are discussed from the stagdpoint of the decomposition of gauge potential.It may be regard as a new basis for the formulation of the fundamental interactions of particle theories. 相似文献
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Structural behaviors of silicon and germanium clusters under the recently proposed modified Stillinger-Weber (SW) potential have been studied by molecular dynamics method along with the con-jugate-gradient optimization. Since the SW potentials have been derived from the properties of bulk materials, it gives relatively large discrepancy when the cluster number is small, e.g. n=3 and 4. When n>4, the ground-state structures under the modified SW potential are close to that from the first-principle calculation. The binding energies are also improved under the modified SW potential. These results may be attributed to the relative enhancement of the two-body term over the three-body term in the modified SW potential, which leads to structures with a preferential coordination number 4. Structural behaviors of germanium clusters are similar to those of silicon. 相似文献
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本文采用一种新的变分波函数描述GaAs/Ga1-xAlxAs窄量子阱中的浅施主基态,并计算了杂质基态波函数和结合能。计算所得数值结果表明正确考虑窄量子阱与杂质势间的耦合作用是极为重要的。
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