类氢原子的强电场电离

强电场情况下,微扰论不再适用,要精确求解Ｓｃｈｒｏｄｉｎｇｅｒ方程．本课题组用数值方法对强电场下类氢原子电离进行了计算,得到基态氢原子的共振态解,与更精确的结果作了比较,证明Ｂｒｅｉｔ－Ｗｉｇｎｅｒ近似在一定误差下是可以接受的． The Schrdinger equation of hydrogen like atoms in a strong electric field is solved by the numerical method instead of perturbation. The resonance ionization of hydrogen atom ground state is computed and comparing with exact result and Breit Wigner parametrisation is useful.     

电场诱导水的太赫兹透射特性研究

许多生物分子自身的转动、振动或分子团的整体振动模式都位于太赫兹波段内,因此可以利用太赫兹光谱技术对生物分子进行检测.同时又由于太赫兹波的光子能量仅为毫电子伏量级,不会对分子的内部结构造成破坏,所以太赫兹时域光谱技术在生物检测方面具有良好的应用前景.众所周知,绝大多数的生物分子只有在液体条件下才能发挥其生物活性,所以研究...     

电场中Rydberg原子的常数标度能谱方法

标度能谱理论能够简化外场谱及可以经典方法理解原子外场谱而倍受关注。本文报道了用于电场中Rydberg原子常数标度能谱实验研究的装置以及有关的计算机控制、采集及处理系统。该系统对能量E和电场F进行同步控制以保持标度能谱ε=E/F为常数，并成功地得到Rydberg态Sr原子在标度能ε=-3.0时的标度能谱，经过傅里叶变换，获得了电场中Sr原子的电子回归谱。     

The Electric Field Outside a Stationary Resistive Wire Carrying a Constant Current

We present the opinion of some authors who believe there is no force between a stationary charge and a stationary resistive wire carrying a constant current. We show that this force is different from zero and present its main components: the force due to the charges induced in the wire by the test charge and a force proportional to the current in the resistive wire. We also discuss briefly a component of the force proportional to the square of the current which should exist according to some models and another component due to the acceleration of the conduction electrons in a curved wire carrying a dc current (centripetal acceleration). Finally, we analyze experiments showing the existence of the electric field proportional to the current in resistive wires.     

Compton Scattering and Induced Compton Scattering in a Constant Electromagnetic Field

The spectral and angular distributions for the Compton effect in a constant electro-magnetic field are obtained. The possibility of the existence of the induced Compton scattering in an external field (i.e. two-photon emission, one of the two photons being induced by the incident wave) is demonstrated. In the case of a constant magnetic field the deviation from the Klein-Nishina formula of the obtained distribution for the Compton effect as well as the behaviour of the distribution for the induced Compton effect are discussed. The optimal region of the parameters for the possible experimental test of these effects is given.     

Nondipole Effects in Atomic Ionization Induced by an Intense Counter-Rotating Bicircular Laser Field

Nondipole effects occurring in the process of atomic ionization by an intense, mid-infrared, counter-rotating bicircular laser field are investigated using the strong-field approximation with leading-order nondipole corrections. The time integrals appearing in the expression for the differential ionization rate are computed in two ways: numerically, and by applying the saddle-point approximation. The nondipole corrections introduce an asymmetry in the photoelectron momentum distribution along the field propagation direction. The asymmetry is quantified by the partial average value of the propagation-direction momentum component of the photoelectrons and by the normalized difference of the differential ionization rates computed including and excluding the nondipole corrections. Using the saddle-point approximation, it is investigated how the nondipole corrections change the solutions for direct photoelectrons and how this affects the momentum spectra. The impact of nondipole corrections increases with increasing photoelectron energy. Analysis of the complete photoelectron spectra including both direct and rescattered photoelectrons shows that, in the low-energy region, a shift against the propagation direction occurs. The partial average of the propagation–direction momentum component in the rescattering region exhibits a plateau structure and also a local minimum structure that was recently observed in an experiment with a linearly polarized laser field (Lin et al., Phys Rev. Lett. 128, 023201 (2022)).     

偏振光激发的Sr原子电偶极辐射

原子与激光场相互作用产生的自发辐射可以用经典电偶极辐射理论很好的描述.通过改变与Sr原子束相互作用激光的偏振方向,分析探测Sr原子束荧光强度的变化,测定了在远场区的电偶极辐射特性.Sr原子电偶极子在远场区辐射能量的空间方向分布满足sin2θ关系,利用这一规律可以有效地探测到最强的荧光光谱.     

Dynamics of the Photoinduced Rotation of a Spherical Particle in a Constant Electric Field

Technical Physics - The rotation of a spherical particle in a constant electric field (an effect found earlier) has been analyzed. The particle is illuminated to induce the electric dipole moment...     

对感生电场计算方法的探讨

对于感生电场的计算问题,在大学电磁学教材中一般都是利用反证法证明螺线管管内外的E感线都是与螺线管轴线相垂直的同心圆.笔者在此利用解析法和类比法两种方法来证明螺线管管内外的E感线都是与螺线管轴线相垂直的同心圆,并在此基础上计算了E感的大小,以供教学参考.     

The Effective Ionization of Air and Oxygen in a Near-Critical Electric Field at High Pressures

The effective ionization of air and oxygen at early stages of electric discharge development at medium and high pressures is analyzed. Ionization in an applied field with the participation of background electrons, electron sticking to and detachment from oxygen atoms and molecules, and recharging and conversion of negative ions is considered. The dependence of ion-molecular processes on external field is taken into account. The effective ionization value is shown to be different in constant and microwave fields. The effective air ionization values obtained in a microwave field are in agreement with the experimental data. It is shown that background electrons determine the possibility of effective ionization, whereas conversion processes determine the existence of a threshold E/N value, where E is the electric field strength and N is the density of neutral particles.     

硅材料场致等效二阶极化率张量的研究

具有反演对称中心的硅单晶在电场作用下体内的反演对称中心消失,因而理论上应产生偶数阶非线性极化率。从理论上根据矢量与张量的作用,利用(eχf2f)=χ(3).E这一关系和张量变换理论系统地阐述了硅材料在内建电场或外加电场的作用下,具体在方向分别沿[111][、110]和[001]的电场作用下,得到的等效二阶极化率张量(eχf2f)分别与C3v、C2v和C4v点群的二阶极化率张量具有相同的形式,说明在物理性质方面,硅的对称性由Oh群在相应方向电场作用下分别被降低为C3v、C2v和C4v群,因此应该具有相应对称性晶体的二阶非线性光学性质;提出了电场E沿任意方向时硅的等效二阶极化率张量e(χf2f)的计算方法,对研究硅材料和其他具有反演对称中心材料的场致二阶非线性光学性质实验具有指导意义。     

Measurement of Ionization Threshold of Ultracold Cesium Rydberg Atoms in Static Electric Field

We investigate the field ionization spectra of ultracold cesium Rydberg atoms in dc electric field. The ionization thresholds of different electric fields are measured and shift of the ionization threshold relative to field-free ionization threshold is accurately described by （6.06±0.14）F1/2, which is in good agreement with the classical saddle-point model for field ionization. We obtain the field-free ionization threshold of cesium （6P3/2） as 19674.89 ± 2.99 cm^-1 by fitting experimental data.     

Ionization of Atoms in a Thermal Field

We study the stationary states of a quantum mechanical system describing an atom coupled to black-body radiation at positive temperature. The stationary states of the non-interacting system are given by product states, where the particle is in a bound state corresponding to an eigenvalue of the particle Hamiltonian, and the field is in its equilibrium state. We show that if Fermi's Golden Rule predicts that a stationary state disintegrates after coupling to the radiation field then it is unstable, provided the coupling constant is sufficiently small (depending on the temperature). The result is proven by analyzing the spectrum of the thermal Hamiltonian (Liouvillian) of the system within the framework of W ^*-dynamical systems. A key element of our spectral analysis is the positive commutator method.     

Rotation of a Spherical Particle with Electrical Dipole Moment Induced by Steady Irradiation in a Static Electric Field

Rotation of a spherical particle in a static electric field and under steady irradiation that induces an electric dipole moment in the particle is studied for the first time. Along with the general treatment of the phenomenon, we analyze possible mechanisms underlying the photoinduction of dipole moment in the particle. Estimations of the angular velocity and the power expended by the rotating particle are provided. The indicated characteristics reach their maximum values if the size of particles is within the range of 10 nm to 10 μm.     

Micromagnetic Structures Induced by an Inhomogeneous Electric Field in Magnetically Uniaxial Films with a Flexo-Magnetoelectric Effect

Physics of the Solid State - The features of the manifestation of the flexo-magnetoelectric effect in magnetically uniaxial films under the local influence of an electric field on their surface are...     

静电场中零电势点的确定和电势的计算

在静电场中,零电势点位置的确定,对电势计算的方便与否起着致关重要的作用.下面就4种情况,简述零电势点位置的确定及相应电势的计算公式.1 点电荷电场中各点电势的计算 例1 设一带电量为Q的点电荷,放在相对电容率为εT的无限大均匀电介质中,求空间各点的电势.     

ZrNCl薄层中基于固体离子导体场效应管的电场诱导的超导电性

场效应晶体管(FET)可以通过电场可逆调控材料的载流子浓度,是一种控制二维材料系统电学性质的有效方法.最近,作者实验室发明了一种新的场效应晶体管器件,它利用固体离子导体(SIC)作为栅介质,通过电场驱动锂离子进出样品来调控样品的载流子浓度,从而控制样品的物理性质和相变.在本论文中,作者利用这种新型的固体离子导体基场效应管器件(SIC-FET)成功地调控了ZrNCl薄层的电学性质.通过施加电场,将固体锂离子导体中的锂离子插入ZrNCl薄层样品中,实现了样品从绝缘体到超导体的转变,最佳超导电性的中点临界温度约为15.1K.实验结果表明,固体离子导体基场效应管器件具有在层状材料中引入载流子的优异性能,该器件将是寻找新的超导体和其他新奇电子相的有效途径.