Investigating the hydrogen atom in crossed external fields by the method of moments

Recurrence relations of perturbation theory for the hydrogen ground state are obtained. With the aid of these relations, polarizabilities in constant mutually perpendicular electric and magnetic fields are computed up to the 80th order of perturbation theory. The high-order asymptotic expression is compared with its semiclassical estimate. For the case of an arbitrary relative orientation of external fields, a general sixth-order formula is given. The energy and the width of the ground state are obtained by means of a perturbation-series summation.     

Electric-field-induced energy spectra and dispersions of ZnO/MgxZn1−xO MQWs

The energy spectra and dispersion relations of carriers in the presence of an electric field applied along the growth direction in ZnO/Mg_xZn_1−xO multiple quantum wells (MQW) are calculated using the asymptotic transfer method (ATM) on the basis of the quasistationary state approximation. The energy spectra of the carriers induce some quasi-bound levels under electric fields. The dispersion relations for the energy of the ground state and lower excitation states still have parabolic shapes for both the electrons and the heavy holes in the presence of a moderate electric field. Our results also reveal that the number of energy levels increases with increasing number of ZnO quantum wells and that the energies increase with both increasing Mg composition x and electric field strength.     

Optical property and collective excitation of plasmon in a multiple-quantum-well superlattice in electric field

A finite type-I superlattice with different dielectric media on either side of the surfaces is considered under a perturbing electric fields parallel to the superlattice axis on the basis of an infinite square potential well. Using the random-phase approximation, the density–density correlation function including intra- and inter-level transitions in a multiple-quantum-well (MQW) is calculated. The dispersion relations for the surface and the bulk states are obtained as functions of the momentum wave vector and the averaged electric field strength over the quantum well. The Raman intensities due to the bulk and the surface plasmons for the intra- and the inter-level transitions are also obtained for incoming light energy.     

Polarized Spacetime Foam

An approximate model of a spacetime foam is presented. It is supposed that in the spacetime foam each quantum handle is like to an electric dipole and therefore the spacetime foam is similar to a dielectric. If we neglect of linear sizes of the quantum handle then it can be described with an operator containing a Grassman number and either a scalar or a spinor field. For both fields the Lagrangian is presented. For the scalar field it is the dilaton gravity + electrodynamics and the dilaton field is a dielectric permeability. The spherically symmetric solution in this case give us the screening of a bare electric charge surrounded by a polarized spacetime foam and the energy of the electric field becomes finite one. In the case of the spinor field the spherically symmetric solution give us a ball of the polarized spacetime foam filled with the confined electric field. It is shown that the full energy of the electric field in the ball can be very big.     

电磁场统一性质的三维描述

论述了电场与磁场本质上的统一性质,构造了三维空间中电磁场的统一场量,给出它的方程、场量的模方与能量和动量的关系,发现三维空间中的统一场量自身的标积竟然是相对论变换下的不变量．     

On the diffusivity-mobility ratio of the carriers in n-channel inversion layers on ternaryChalcopyrite semiconductors

An attempt is made to study the Einstein relations for the diffusivity-mobility ratios of the carriers in n-channel inversion layers on ternary chalcopyrite semiconductors under both weak and strong electric field limits, taking n-channel inversion layers on CdGeAs₂ as an example. It is found, on the basis of newly derived 2D E-k_s dispersion relations of the conduction electrons for both the limits by considering the various types of anisotropies in the energy band, that the ratios increase with increasing surface electric fields for both the limits and the theoretical results are in qualitative agreement with the suggested experimental method of determining the Einstein relation in degenerate semiconductors having arbitrary dispersion law. The corresponding well-known results for isotropic twoband Kane model are also obtained from the expressions derived.     

Charge-carrier and polaron hopping mobility in disordered organic solids: Carrier-concentration and electric-field effects

The effective-medium approximation (EMA) analytical theory is advanced further to describe charge transport at arbitrary charge-carrier concentration in a disordered organic material with superimposed polaron effects. A key point of this model compared to the previous treatment [Phys. Rev. B 76 (2007) 045210] is that it is formulated for arbitrary electric fields and is able to describe consistently both the carrier-concentration and field dependences of charge mobility. The mobilities of both bare charge carriers and polarons were calculated using the Miller–Abrahams and polaron jump rate models, respectively. An excellent quantitative agreement was obtained between the theoretical calculations and the recent numerical simulations of the field- and carrier-density dependences of the mobility for bare charge carriers using the same parameters. The polaronic carrier density effect was also calculated using the complete Marcus jump rate equation and straightforward EMA configurational averaging, and the results compared to that obtained with the use of the symmetrical jump rate model and the effective transport energy concept. This study confirms that a strong dependence of carrier mobility upon increasing carrier density and electric field, which has conventionally been observed in experiment for numerous organic semiconducting materials, is incompatible with the notion of large polaron binding energy in these materials, implying that the energetic disorder plays a dominant role.     

Penetration of electric fields induced by surface phonon modes into the layers of a semiconductor heterostructure

The penetration of electric fields induced by surface optical phonons into adjacent layers of semiconductor heterostructures is investigated. The mechanical displacement of ions, the corresponding electric fields, and the dispersion relations for surface phonon modes in single and double heterostructures are calculated within the macroscopic phenomenological model of optical lattice vibrations. To estimate the penetration depth of the surface electric fields, the intraband relaxation rate of the electron subsystem of a quantum dot embedded in a heterostructure, related to these fields, is calculated as a function of the distance from the interface between the media to the quantum dot.     

One photon and macroscopic B cyclic equations: Reply to van Enk

The B cyclics of electrodynamics, which relate transverse and longitudinal fields in vacuo, are one photon relations which are also valid on a macroscopic scale. In the same way, the Maxwell equations in the received view were originally phenomenological relations between electric and magnetic fields, but, in the received view are also written down for one photon. Point by point replies to van Enk are given.     

Symmetry transformations and reciprocity relations in the theory of multicomponent dielectric media

Characteristics of the formation of a dipole electric field are established for multicomponent fiber composites having a regular distribution of inclusions in the matrix. It is shown that these media are characterized by symmetry transformations of the average electric fields. These symmetry transformations yield reciprocity relations for the effective parameters. Various forms of these relations are given and their physical interpretation is presented.     

外电场下BH分子势能函数

运用密度泛函B3P86方法和cc-PV5Z基组,获得了BH分子基态在不同外电场下的键长、偶极矩和振动频率等物理性质参数.通过分析物理性质参数,判断离解电场所处的范围,设置合适的参数扫描该范围的单点能获得势能曲线.结果表明物理性质参数和势能值随外电场的变化而变化,特别是在反向电场中.利用Morse势模型拟合无外场下势能函数,得到的拟合参数与实验值吻合较好,采用偶极近似构建外电场下的势能函数模型,编制程序拟合对应的势能函数,得出拟合参数,再计算临界离解电场参量,结果与数值计算值较为一致,说明构建的模型是可靠和准确的.为分析外场下分子光谱、动力学特性和分子Stark效应冷却囚禁提供理论参考.     

A method of analysis of distributions of local electric fields in composites

A method of prediction of distributions of local electric fields in composite media based on analysis of the tensor operators of the concentration of intensity and induction is proposed. Both general expressions and the relations for calculating these operators are obtained in various approximations. The analytical expressions are presented for the operators of the concentration of electric fields in various types of inhomogeneous structures obtained in the generalized singular approximation.     

Effects of Crossed Electric and Magnetic Fields on Shallow Donor Impurity Binding Energy in a Parabolic Quantum Well

We have calculated variationally the ground state binding energy of a hydrogenic donor impurity in a parabolic quantum well in the presence of crossed electric and magnetic fields. These homogeneous crossed fields are such that the magnetic field is parallel to the heterostructure layers and the electric field is applied perpendicular to the magnetic field. The dependence of the donor impurity binding energy to the well width and the strength of the electric and magnetic fields are discussed. We hope that the obtained results will provide important improvements in device applications, especially for a suitable choice of both fields in the narrow well widths.     

外电场作用下SF_6分子结构与红外光谱

采用密度泛函LSDA方法,在6-311++g(3df,3pd)基组水平上研究了不同外电场下SF_6分子的几何结构、偶极矩、能级分布和红外光谱的变化规律,并利用杂化CIS方法研究了SF_6分子的前9个激发态的激发能、波长和振子强度随外电场的变化情况.结果表明:X轴向上的1S-6F键长受到外场影响最大,随着外电场的增加可能最先趋于断裂;偶极矩随外场的增加而增大,分子总能量随外场的增加而减小;LUMO能级较HOMO能级受外电场影响大,能隙随外场增大而减小;红外光谱吸收峰随外场增大而分开,同时部分原本不具有红外活性的振动模式变成了具有一定的红外活性;激发波长、振子强度、激发能也受外电场影响,但随电场变化比较复杂.     

外电场作用下SF6分子结构与红外光谱

采用密度泛函LSDA方法,在6-311++g(3df,3pd)基组水平上研究了不同外电场下SF6分子的几何结构、偶极矩、能级分布和红外光谱的变化规律,并利用杂化CIS方法研究了SF6分子的前9个激发态的激发能、波长和振子强度随外电场的变化情况。结果表明：X轴向上的1S-6F键长受到外场影响最大,随着外电场的增加可能最先趋于断裂;偶极矩随外场的增加而增大,分子总能量随外场的增加而减小;LUMO能级较HOMO能级受外电场影响大,能隙随外场增大而减小;红外光谱吸收峰随外场增大而分开,同时部分原本不具有红外活性的振动模式变成了具有一定的红外活性;激发波长、振子强度、激发能也受外电场影响,但随电场变化比较复杂。     

外电场下TCNQ的激发与光谱性质研究

采用密度泛函B3PLY方法优化了不同外电场下TCNQ分子的基态稳定构型、电偶极矩和分子的总能量，并且分析了TCNQ分子的HOMO-2到LUMO+2轨道的能量变化。然后利用杂化CIS-DFT方法在同样的基组下计算了外电场下TCNQ分子的前9个激发态的激发能、波长和振子强度，结果表明在没有外电场的情况下，TCNQ分子只有一个激发态能够激发，从基态跃迁到第1激发态。在有外电场的作用下，总能量随外电场的增加而逐渐减少，偶极矩随外电场的增加而不断增加。其前线轨道的能量也随外电场的增加不断减少，轨道分布也受外电场很大的影响。另外，外电场对TCNQ分子的激发波长也产生了一定影响。     

CH自由基在外电场中的分子结构和势能函数

运用密度泛函B3P86方法,结合Dunning的相关一致五重基cc-PV5Z,获得了CH自由基分子在不同外电场中的键长、偶极矩和振动频率等物理性质参数.通过分析物理性质参数的变化,判断离解电场所处的范围,设置合适的参数扫描该范围的单点能获得势能曲线.结果表明物理性质参数和势能值随外电场的变化而变化,且反向电场中变化幅度较大.利用Morse势模型拟合无外场下势能函数,得到的拟合参数与实验值吻合较好,采用偶极近似构建外电场下的势能函数模型,编制程序拟合对应的势能函数,得出拟合参数,进而计算临界离解电场参量,结果与数值计算值较为一致,说明构建的模型是可靠和准确的.这为分析外场下分子光谱、动力学特性和分子Stark效应冷却囚禁提供重要的理论和实验参考.     

外电场下TCNQ的激发与光谱性质研究

采用密度泛函B3PLY方法优化了不同外电场下TCNQ分子的基态稳定构型、电偶极矩和分子的总能量,并且分析了TCNQ分子的HOMO-2到LUMO+2轨道的能量变化。然后利用杂化CIS-DFT方法在同样的基组下计算了外电场下TCNQ分子的前9个激发态的激发能、波长和振子强度,结果表明在没有外电场的情况下,TCNQ分子只有一个激发态能够激发,从基态跃迁到第1激发态。在有外电场的作用下,总能量随外电场的增加而逐渐减少,偶极矩随外电场的增加而不断增加。其前线轨道的能量也随外电场的增加不断减少,轨道分布也受外电场很大的影响。另外,外电场对TCNQ分子的激发波长也产生了一定影响。     

Fermi-Dirac statistics for free electrons in uniform electric and magnetic fields

In this paper we study the De Haas-Van Alphen effect when an electric field is present. We prove that for sufficiently weak electric fields, where the conditions are favorable for energy quantization, the free energy is a quasi-periodical function with respect to the fields. As a consequence we find, for the magnetic susceptibility, periodical expressions which are easily reduced to the ones known for the De Haas-Van Alphen effect when the electric field vanishes.     

Theoretical analysis of THz Sommerfeld wave propagation on metal wire at normal temperature

In this paper, THz Sommerfeld wave propagation on single bare metal wire and dielectrically coated metal wire waveguide is presented by the numerical calculation from 0.1 THz to 1 THz. The influences of different metal and different dielectric materials on the electric field distribution around the metal wire are analyzed. The characteristics of energy coupling in the coated metal wire with different metal and dimensions are also proposed. The analysis results release a fundamental characteristic for describing the surface wave propagation along the dielectrically coated metal wire at terahertz frequencies, and moreover, the analysis results also suggest that a simple dielectrically coated metal-wire can be used for terahertz applications due to its energy concentration, as compared to the single bare metal wire.