Solitary deflection waves on the supersonic domain wall in yttrium orthoferrite

The moving antiferromagnetic vortices are accompanied by solitary deflection waves. These waves allow to investigate generation and nonlinear dynamics of the antiferromagnetic vortices on the moving domain wall with the help of the two- and three-fold digital high speed photography. On the quasi-relativistic domain wall the vortex dynamics is quasi-relativistic with the limiting velocity c=20 km/s, which is equal to the spin-wave velocity. The solitary deflection waves dynamics can be explained assuming existence of the gyroscopic force. A theory for the gyroscopic force in the orthoferrite domain wall is elaborating by A.K. Zvezdin et al. currently. We present a comparison of the theoretical and experimental results on the dynamics of the solitary deflection waves, which accompany the antiferromagnetic vortices in the domain wall of orthoferrites.     

The possibility of cyclotron echo generation in graphene on a SiC substrate

The possibility of cyclotron echo generation in graphene on a silicon carbide substrate has been predicted on the basis of the direct quasi-classical Monte Carlo simulation. The nature of this effect is the quasi-relativistic dependence of the effective mass of charge carriers on their velocity. The numerical values of the field strengths at which the effect should be most pronounced are found.     

On the Poincaré-invariant equations for particles with variable spin and mass

The Poincaré-invariant equations without redundant components, describing the motion of a particle which can be in different spin and mass states are obtained. The quasi-relativistic equation for a particle with arbitrary spin in external electromagnetic field is found. The group-theoretical analysis of these equations in carried out.     

类铜铅离子自电离速率与双电子俘获强度的扭曲波计算

 采用相对论扭曲波近似方法对高离化态类铜铅离子的自电离速率系数与双电子俘获强度进行了计算。计算结果表明:旁观电子的变化使自电离速率系数呈现出规律性变化。同时用该方计算了Ta元素类铜离子、Au元素类镍离子的自电离速率系数，将结果同相关文献的相对论多参数势方法、准相对论性Hartree-Fock-Relativistic方法以及自旋-轨道劈裂跃迁组模型方法所得结果进行了比较，符合得很好。     

X-ray spectra from laser produced highly ionized hafnium plasma in the 4.1–4.5 Å range

X-ray spectra of highly ionized hafnium atoms have been obtained from laser produced plasmas in the 4.1–4.5 Å range. Using quasi-relativistic configuration interaction calculations of the wavelengths and transition probabilities, the observed spectral band structure can be interpreted as being due to 3d–6f transitions of the NiI—GeI like ionization states of hafnium.     

CPT and Lorentz invariance violation in hydrogen-like atoms

We analyze an approximate solution to the Dirac equation for an electron in a central potential, in particular, in a Coulomb potential, when Lorentz invariance is violated. A quasi-relativistic approximation for the Dirac equation in an external field has been derived. The directivity pattern of spontaneous emission for a polarized hydrogen atom has been found to be asymmetric.     

多组态Dirac-Fock方法与准相对论组态相互作用方法的比较研究

利用多组态Dirac-Fock(MCDF)方法与准相对论组态相互作用方法,分别详细计算了低Z、中Z和高Z原子(离子)各个壳层上电子的束缚能、平均轨道半径、总束缚能、激发能、精细结构能级以及类Ne等电子系列离子的2p53s 1,3P1-2p6 1S0跃迁能,并且对这两种方法的结果进行了数值比较.     

高离化态Cu18+离子的双电子复合及共振转移激发过程的理论研究

在准相对论理论框架下计算了Cu¹⁸⁺离子的双电子复合截面，分析了组态相互作用对截面的影响.基于这些数据，在冲量近似下，通过对靶原子中电子动量分布的卷积，进一步得到了Cu¹⁸⁺与H₂碰撞过程中的共振转移激发截面，并与已有的实验结果作了比较，符合得很好.A 关键词： 双电子复合 共振转移激发     

Lagrangians and Hamiltonians for One-Dimensional Autonomous Systems

An equation is obtained to find the Lagrangian for a one-dimensional autonomous system. The continuity of the first derivative of its constant of motion is assumed. This equation is solved for a generic nonconservative autonomous system that has certain quasi-relativistic properties. A new method based on a Taylor series expansion is used to obtain the associated Hamiltonian for this system. These results have the usual expression for a conservative system when the dissipation parameter goes to zero. An example of this approach is given.     

平均原子模型中Au元素自电离速率的计算

为了得到用于平均原子模型中的自电离速率,采用准相对论组态平均的方法系统计算了Au的不同电离度、不同自电离态的自电离速率,计算时使用的波函数由Cowan程序得到;通过组态到组态的自电离速率得到了nl层次的单电子自电离速率(初态平均、末态平均);在此基础上计算出了n层次的单电子自电离速率,这些数据可用于平均原子模型中自电离及其逆过程的计算。为了验证计算出的数据是否可靠,用细致能级层次的程序计算了部分数据点。通过比较和分析认为,除了少量高l的数据点计算得不够准确之外,当前的数据较为可靠,并用其它程序的计算结果对不准确的数据进行了替换。     

Relativistic density functional calculation of the total energy and Fermi surface of gold

For fcc gold we have studied the total energy, equilibrium lattice constant, bulk modulus and Fermi surface with their dependence on pressure. The self-consistent calculation in the local-density and warped muffin-tin approximation applies the modified augmented-plane-wave band-method. The core levels are treated in a fully relativistic way and the valence levels in a quasirelativistic approximation on the basis of the Foldy-Wouthuysen transformation. Though the Fermi surface properties and especially the dependence of the extremal orbit areas on pressure are in good agreement with other calculations and experimental values, careful convergence tests offer the quasi-relativistic approximation as source of large errors in the properties which are derived from the total energy.     

Thin layers of grey arsenic: A molecular orbital study

A thin layer of grey arsenic has been manufactured by molecular beam epitaxy and its He(I) photoelectron spectrum has been recorded. The quasi-relativistic CNDO/1 method has been used to investigate the band structure of {As}₁₁₄ and {As}₂₂₈ clusters: the DOS profiles and their projections are under question. These data were correlated with the periodic crystal orbitals of the EHT quality. The first excitation energy serves as a better estimate of the energy gap between the filled valence band and the empty conduction band.     

To the description of hadron mass spectrum in the nonrelativistic quark potential model

The comparison of different confinement models of hadrons in non-relativistic quark potential model with the use of hyperspherical functions is carried out in the present work. Numerical values of the masses of non-strange (the lightest) hadrons belonging to the meson octet and baryon decuplet are obtained in this model. The best values of masses are obtained with the potential which incorporates the quasi-relativistic one-gluon exchange and the confinement termAr ⁿ withn=2/3. The natural appearance of the Yukawa-type potential in this model is also discussed.     

类铍离子1s~22snp~3P(n=2～6,Z=5～8)态能级和精细结构参数的理论计算

在准相对论框架下,以多电子原子精细结构哈密顿的球张量形式为基础,借助不可约张量和角动量耦合理论,导出类铍离子1s22snp(n=2-6)3P态精细结构(包括自旋-轨道相互作用、自旋-其它轨道相互作用和自旋-自旋相互作用)和精细结构参数的解析表达式,并利用我们所开发的程序,对各项进行了具体地计算,计算结果与文献符合地较好.     

氩离子原子过程参数的系统计算与评估：Ⅰ电子碰撞激发

利用准相对论扭曲波玻恩近似加交换方法，在组态平均近似下，系统地计算了类氢、类氦、类锂氩离子n≤6的各组态之间的碰撞激发过程截面。并和已有的理论结果进行了详细的对比分析。计算结果和相对论扭曲波近似的计算结果符合得很好，相对偏差一般都小于10％。由于没有考虑共振效应。计算的结果与强耦合方法的计算结果在入射电子能量较低的情况下有较大偏差，其他情况则符合较好，相对偏差一般在15％以内。该方法可以方便地计算大量应用所需的原子过程参数。     

Au等离子体M带5f-3d跃迁的电子离子碰撞激发速率系数

电子离子碰撞激发速率系数在超组态碰撞辐射模型中真实模拟非局域热动力学平衡Au激光等离子体M带谱 5f 3d跃迁中各种复杂电荷态离子的电离态特性 (譬如离子的平均电离度 ,相对丰度和能级布居数 )是必不可少的。基于准相对论多组态Hartree Fock方法和扭曲波玻恩交换近似 ,采用自编的扭曲波程序ACDW (9)和Fit(9) ,从头计算了Au等离子体M带 5f 3d电子离子碰撞激发速率系数。结果表明 :在“神光II”实验装置诊断的电子温度约 2keV ,电子密度约 6× 10 2 1cm-3 范围内 ,这些电子离子碰撞激发参数有利于采用超组态碰撞辐射模型模拟Au的激光等离子体M带 5f～ 3d细致谱的平均电离度和电荷态分布。     

氩离子原子过程参数的系统计算与评估：I 电子碰撞激发

 利用准相对论扭曲波玻恩近似加交换方法，在组态平均近似下，系统地计算了类氢、类氦、类锂氩离子n≤6的各组态之间的碰撞激发过程截面，并和已有的理论结果进行了详细的对比分析。计算结果和相对论扭曲波近似的计算结果符合得很好，相对偏差一般都小于10%。由于没有考虑共振效应，计算的结果与强耦合方法的计算结果在入射电子能量较低的情况下有较大偏差，其他情况则符合较好，相对偏差一般在15%以内。该方法可以方便地计算大量应用所需的原子过程参数。     

夸克模型下的轻介子质量谱

最近,文献[1]将辅助场方法应用于准相对论性夸克模型中,获得了一个解析的非奇异轻介子质量公式。本文将这种方法推广到奇异轻介子的情况,得到了一个味道依赖的轻介子质量公式。结果表明,质量公式预言的低激发态质量谱与实验值吻合良好,平均误差在30 MeV左右。质量公式预言的高激发态质量谱和其他文献（特别是弦模型）的计算相比,也符合较好。Recently, with the help of auxiliary field method, Ref.[1] obtains an analytical mass formula for nonstrange light mesons in quasi-relativistic quark model. In this work, we generalize this method to the case of strange light mesons, and obtain a mesonic mass formula which is flavor-dependent. The results show that the mass of low excitations given by the mass formula are in good agreement with the experimental data and the average error is around 30 MeV. Our mass predictions for the high states also agree well with the other calculations in the literatures, particularly, the string model calculations.     

Generation and gyroscopic quasi-relativistic dynamics of antiferromagnetic vortices in domain walls of yttrium orthoferrite

An unusual nonlinear relation between the velocity of an antiferromagnetic (AFM) vortex along a domain wall (DW) on the DW velocity is detected. This relation has a maximum whose position depends on the topological charge of the vortex. As the DW velocity increases from the value corresponding to the maximum to its limiting value, the AFM-vortex velocity decreases and tends to zero. The total AFM-vortex velocity increases nonlinearly with the DW velocity and levels off at 20 km/s, which is equal to the velocity of spin waves in the linear section of their dispersion law. The experimental data are approximated satisfactorily. The dynamics of AFM vortices in DWs of yttrium orthoferrite, just as the dynamics of the DWs, is quasi-relativistic and gyroscopic.     

Gyroscopic dynamics of antiferromagnetic vortices in domain boundaries of yttrium orthoferrite

It is established experimentally that the magnetic field directed along the b axis has little effect on the velocities of antiferromagnetic vortices in the domain boundary (DB) of yttrium orthoferrite and fails to explain the presence of an appreciable gyroscopic force acting on these vortices. This force is induced by the dynamic canting of magnetic sublattices proportional to the DB velocity. Due to the canting, the velocities of antiferromagnetic vortices depend initially quadratically on the DB velocity, as was experimentally found in this work. The dynamics of antiferromagnetic vortices in the yttrium orthoferrite DBs is gyroscopic and quasi-relativistic, with the limiting velocity of 20 km/s equal to the velocity of spin waves at the linear portion of their dispersion curve.