无反射势的Schrdinger方程严格解的三维推广

文献[1]给出无反射势V(x)=-N(N+1)sech~2x当N为任意正整数时schrodinger方程束缚态和散射态的严格解。本文推广文献[1]的工作,继续给出三维情况下无反射势Schrodinger方程束缚态和散射态的严格解,并得到了与一维情况不同的一些物理结果。     

无反射势的Schr?dinger方程严格解的三维推广

文献[1]给出无反射势V(x)=-N(N+1)sech²x当N为任意正整数时Schr?dinger方程束缚态和散射态的严格解。本文推广文献[1]的工作,继续给出三维情况下无反射势Schr?dinger方程束缚态和散射态的严格解,并得到了与一维情况不同的一些物理结果。 关键词：     

修正Poschl-Teller势的Schrdinger方程束缚态的精确解

将修正Pschl-Teller势的Scbrdinger方程作自变量双曲函数变换,使其转化为普遍的associated-Legendre方程.用级数法解此方程,得到了用普遍的associated-Legendre多项式表示的修正Pschl-Teller势的束缚态的归一化波函数.文献[1—5]中的有关结果都作为特例包含在本文的一般结论之中.     

磁场中与形变势相互作用的表面极化子的有效质量

近年来 ,磁场中极性晶体表面极化子的性质已引起人们的广泛关注。Ｌａｒｓｅｎ[1 ] 采用四级微扰法计算了磁场中二维极化子的基态能量。Ｗｅｉ等[2 ] 用格林函数方法研究了交界面磁极化子的回旋共振质量和频率。本文作者之一[3] 用线性组合算符讨论了磁场中表面极化子的性质。实际上 ,到目前为止 ,对表面磁极化子的研究 ,只限于考虑表面电子只与表面光学 (ＳＯ)声子和体纵光学 (ＬＯ)声子相互作用 ,而忽略了表面电子与表面声学 (ＳＡ)声子相互作用。对电子通过形变势与晶格声学振动相互作用形成的准粒子 声学形变势 (ＡＤＰ)极化子性质的研…     

用质点源方法计算二维系统电磁脉冲问题中的初级电流

本文用质点源方法求解了二维SGEMP问题中的初级电流,在麦克斯韦方程组,次级电子的能量方程、速度方程和其他计算条件与文献[1]相同的条件下,得到的初级电流和电磁脉冲的结果与[1]的结果符合较好。     

液态金属及非晶态中的电导率——相干势近似

本文在紧束缚模型内得到了液态金属和非晶态中电子电导率的相干势近似(CPA)结果,用文献[4]提出的处理单格点图形的系统方法可以得到平均双粒子格林函数的近似方程,这里采用具有短程序的点阵-气体模型,液态金属和非晶态金属相对应的CPA方程可以从点阵-气体模型的极限求得,这样得到的目洽方程包括所有的单格点图形,具有CPA的所有性质。 关键词：     

GaN真空面电子源光电发射机理研究

采用Cs源持续、O源断续的交替方法成功激活了GaN光电阴极,原位测试了透射模式下的光谱响应曲线,获得了透射模式下高达13%的量子效率.从一维定态薛定谔方程入手,得到了GaN真空面电子源材料的电子透射系数的表达式.对于一定形状的阴极表面势垒,电子透射系数决定于入射电子能量、表面势垒的高度和宽度.根据具有负电子亲和势(NEA)特性的透射式GaN光电阴极的能带及Cs,O覆盖过程中阴极表面势垒的变化情况,结合双偶极层[CaN(Mg):Cs]:O-Cs表面模型,分析了GaN真空面电子源材料NEA特性的形成原因.研究表明:Cs,O激活过程中形成的双偶极层对电子逸出起促进作用,双偶极层的形成是材料表面真空能级下降的原因. 关键词： GaN 电子源 透射系数 双偶极层     

关于阻抗尖劈绕射问题的Malyuzhinets泛函方程的解

在文献[1]中,Malyuzhinets给出了阻抗尖劈绕射问题的解。关键是Malyuzhinets泛函方程的求解,但文献[1]并未给出如何得到解的,文献[2]利用无穷乘积理论给出了Malyuzhinets泛函方程的详细求解过程,但其中存在一些错误和不明确之处。本文改正了文献[2]的错误,同时也给出了Malyuzhinets泛函方程的另一种较简单的解法以兹比较。     

能量无关N-N介子交换势中的张量力

本文应用文献[1]中提出的方法导出了能量无关N-N介子交换势, 并讨论了其中的张量力成份.     

负电子亲和势GaN光电阴极铯吸附机理研究

为了得到铯吸附与阴极电子亲和势变化之间的定量关系,利用NEA光电阴极激活评估实验系统对GaN光电阴极进行了铯激活.根据半导体光电发射理论和双偶极层模型,通过对电子亲和势随铯覆盖度变化的实验结果进行拟合运算,得到电子亲和势与铯覆盖度之间的函数关系式.分析了铯的吸附机理,得到激活过程中铯的吸附过程与GaN材料有效电子亲和势下降之间的关系.实验表明:负电子亲和势GaN光电阴极材料在铯激活时光电流随着铯覆盖度的增加而从本底值增为极大值,激活过程中GaN电子能量分布曲线低动能截止点的位置决定于铯的覆盖度.当铯的覆盖度从0、1/2、2/3到1个单层变化时,低动能截止点依次向左移动,当覆盖度从0增加到1个单层时,低动能截止点向左移动了约3eV的距离.研究表明,低动能截止点左移本质上是由于对电子逸出起促进作用的有效偶极子[GaN(Mg):Cs]数量的增多造成的,有效偶极子数量的增多带来了材料表面真空能级的下降.     

One-body electron dynamics in a free electron laser

The free electron laser is analyzed by solving the one-body classical Lorentz force equation in the presence of periodic magnetic field and a plane electromagnetic wave. Phase space paths for electrons are related to those of a simple pendulum and describe laser gain, saturation, and coherent electron beam modulation.     

Calculation of radiant energy in free electron lasers without inversion

The equations of motion of particles in free electron lasers without inversion (FELWI) were obtained using the Hamilton formalism. An one-dimensional decoupled phase equation of the type of mathematical pendulum equation was derived in the case of weak signal. For practical estimates, this equation was solved together with the equation of electron energy change within the frameworks of perturbation theory, and expressions for gain were obtained in FEL regime and for the output angle from the first undulator. Expressions for the gain coefficient, the phase and the energy change were found as functions of the parameters of beam and of the device.     

利用机械能守恒求解非惯性系单摆的振动周期

由于不同的非惯性系具有不同的加速度,导致单摆在不同的非惯性系中具有不同的振动周期,所以有必要掌握非惯性系下单摆振动周期的计算.基本的计算方法是利用非惯性系动力学方程,结合受力分析求解,但这种方法既要考虑惯性力,又需要进行力的分解,比较麻烦.本文通过引入惯性力势能,给出非惯性系机械能守恒定律,并利用机械能守恒定律对处于特定非惯性系中的单摆周期进行分析计算,得出非惯性系中单摆的振动周期不仅与单摆自身属性有关,而且与非惯性系的运动加速度或角速度有关的结论.     

Basic and Fluctuating Periodic Instantons in Quantum Tunneling

Under condition of four potential fields, equations of motion and fluctuations in imaginary time are utilized to analytically derive the basic and fluctuating periodic instantons. It is shown that the basic instantons satisfy the elliptic or simple pendulum equations and their solutions are Jacobi elliptic functions, and fluctuating periodic instantons satisfy the Lam′e equation and their solutions are Lame functions. These results indicate that there exists the common solution family for different potential fields which are called the super-symmetry family.     

用Hartree-Fock-Slater-Boltzmann-Saha模型研究等离子体细致组态原子结构及其状态方程

用平均原子自洽势计算等离子体的自由电子背景，通过在Hartree Fock Slater自洽场原子结构中引入背景修正计算离子组态结构，为Boltzmann Saha方程提供能级参数，再通过调节共同的背景电子实现Saha方程与Hartree Fock Slater方程的耦合，自洽求解等离子体细致组态原子结构，提高Saha方程的计算精度.以碳、铝等离子体作为算例，分析了本方法的适用范围. 关键词： 原子结构 Boltzman Saha方程 状态方程     

自由电子激光器中的电子阻尼运动

建立了有阻尼项的摆方程,在小信号情况下,对方程进行了迭代求解.由解得的结果得到了增益函数的表达式.特别对弱阻尼和过阻尼情况进行了计算,分别得到了相应的增益函数简化公式.对阻尼项的来源和物理意义进行了详细的讨论. 关键词：     

Free Massive Fermions¶Inside the Quantum Discrete sine-Gordon Model

We extend the notion of space shifts introduced in [FV3] for certain quantum light cone lattice equations of sine-Gordon type at root of unity (e.g. [FV1,FV2,BKP,BBR]). As a result, we obtain a compatibility equation for the roots of central elements within the algebra of observables (also called current algebra). The equation, which is obtained by exponentiating these roots, is exactly the evolution equation for the?“classical background” as described in [BBR]. As an application for the introduced constructions, we derive a one to one correspondence between a special case of the quantum light cone lattice equations of sine-Gordon type and free massive fermions on a lattice, as a special case of the lattice Thirring model constructed in [DV]. Received: 2 December 1996 / Accepted: 19 January 1999     

Self-consistent solution of Kohn-Sham equations for infinitely extended systems with inhomogeneous electron gas

The density functional approach in the Kohn-Sham approximation is widely used to study properties of many-electron systems. Due to the nonlinearity of the Kohn-Sham equations, the general self-consistence searching method involves iterations with alternate solving of the Poisson and Schrödinger equations. One of problems of such an approach is that the charge distribution renewed by means of the solution of the Schrödinger equation does not conform to boundary conditions of the Poisson equation for the Coulomb potential. The resulting instability or even divergence of iterations manifests itself most appreciably in the case of infinitely extended systems. The known attempts to deal with this problem are reduced in fact to abandoning the original iterative method and replacing it with some approximate calculation scheme, which is usually semi-empirical and does not permit to evaluate the extent of deviation from the exact solution. In this work, we realize the iterative scheme of solving the Kohn-Sham equations for extended systems with inhomogeneous electron gas, which is based on eliminating the long-range character of Coulomb interaction as the cause of tight coupling between charge distribution and boundary conditions. The suggested algorithm is employed to calculate energy the spectrum, self-consistent potential, and electrostatic capacitance of the semi-infinite degenerate electron gas bounded by an infinitely high barrier, as well as the work function and surface energy of simple metals in the model with homogeneous distribution of positive background. The difference between self-consistent Hartree solutions and those taking into account the exchange-correlation interaction is analyzed. The comparison with the results previously published in the literature is carried out. The case study of the metal-semiconductor tunnel contact shows this method as applied to an infinitely extended system where the steady-state current can flow.     

Charge symmetry of wave functions for an electron in a quantized electromagnetic wave field

The violation of charge symmetry in the known [1] wave functions for an electron in a quantized wave field is considered. An attempt is made to modify the equations and to construct solutions free of this deficiency.     

Surface tension,shear viscosity and isothermal compressibility of liquid C60 along the liquid-vapour coexistence

The correlations between the surface tension, shear viscosity, and isothermal compressibility, are investigated for liquid C₆₀ at extended regions of temperature and pressure. An improved equation of state [EOS] is employed, based on hard-core plus three Yukawa potential [HC3YK] which facilitates the analytically accurate series mean spherical approximation [SMSA] formalism for the free energy. The present equation of state is utilized to obtain analytical expressions for the thermodynamic functions of interest and discuss the validity of their mutual relations along the spinodal curve of C₆₀.