Multiple Anticrossings of Magnetic Hyperfine Atomic Sublevels

An analysis of the anticrossing of several magnetic hyperfine sublevels of the same fine structure level is made. An expression for the resonance fluorescence signal is derived. Physical requirements for observation are discussed and lineshapes computed.     

Electroweak Corrections with Allowance for Hard Bremsstrahlung in Polarized Bhabha Scattering

Physics of Atomic Nuclei - A total set of one-loop electroweak radiative corrections, including the contribution of the emission of real hard photons (hard-bremsstrahlung contribution), to...     

Resonant Scattering of Gravitational Waves with Electromagnetic Waves

A certain class of exact solutions of Einstein Maxwell spacetime in general relativity is discussed to demonstrate that at the level of theory, when certain parametric resonance condition is met, the interaction of electromagnetic field with a gravitational wave will display certain Lyapunov instability and lead to exponential amplification of a gravitational wave train described by certain Newman–Penrose component of the Weyl curvature. In some way akin to a free electron laser in electromagnet...     

Dimensional Magnetoacoustic Effects in Resonant Scattering of Longitudinal Phonons by a Layered Magnetic Structure

JETP Letters - The indirect spin–spin interaction through the field of virtual phonons polarized in the plane of incidence in a magnetic layer with slip boundaries in an unbounded nonmagnetic...     

Hyperfine Spectroscopy with Nuclear Resonant Scattering of Synchrotron Radiation

Since its observation in 1985 nuclear resonant scattering of synchrotron radiation has become an excellent tool to study hyperfine interactions in solids. It combines the advantages of both local probe experiments and scattering techniques and gives valuable information on magnetic and electronic structures in case of NFS experiments. Experiments benefit from the outstanding beam quality of 3rd generation synchrotron radiation sources, as the small beam size and divergence. This revised version was published online in August 2006 with corrections to the Cover Date.     

Modeling of the Kinetics of Intramolecular Processes and Transient Spectra with Allowance for Nonradiative Transitions

It has been shown that the kinetics of intramolecular processes and time-resolved spectra with allowance for the quantum beats of the resonant states of isomers or isolated subsystems of levels of one isomeric form can be described with the use of a molecular model interpreting the effect of beats as a nonradiative transition. We have obtained an expression for the nonradiative transition probability, which is directly proportional to the beat frequency and depends oscillatorily on time, thus modeling the effect of beats. The parameter of the molecular system model is the beat frequency directly related to the parameter characterizing the intramolecular interisomeric interactions (the corresponding nondiagonal element of the energy matrix) rather than the value of the nonradiative transition probability. The character of the change in the level populations and, accordingly, in the band intensities in the spectra in the proposed model is in good agreement with the experiment, including the fine structure of the time dependences — oscillations of the line intensities. In analyzing the temporal experiment with a high resolution, it is necessary to take into account the instrument function leading to quantitative and qualitative changes in the time dependences. The traditional model of nonradiative transitions with a constant probability value has a very limited range of applicability — very high beat frequencies compared to the probability of optical transitions.     

Calculations of Magnetic Fields in Ferromagnetic Cylindrical Rods with Allowance for Noncollinearity of Magnetization Vectors

In the present work, magnetic parameters of ferromagnetic cylindrical rods are calculated with allowance for noncollinearity of the magnetization vector with the rod magnetization direction.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 63–59, February, 2005.     

Surface and Interface Investigations by Nuclear Resonant Scattering with Standing Waves

Hyperfine Interactions - The main features of the reflectivity spectroscopy (“coherent spectroscopy”) in energy, time and angular scales are considered. They are the enhancement or...     

A Theory of the Multimode Resonant Raman Scattering Compared with the Experiment

The dynamics of the Resonant Raman Scattering (RRS) of multimode broadband lasers is described and resolved without neglecting the phase and cavity effects. The multimode pump structure leads to an equivalent Raman structure by mixing interaction. When the stokes and the pump modes have the same phase, the forward multimodal Raman scattering shows a gain equivalent to the gain of a single mode pump with an equivalent mean power, so that in a Raman resonator the Raman modes can be synchronously amplified to the saturated power until the de phasing destroys the Raman conversion. All these effects have been experimentally observed. Besides an incoherent scattering process is always present in competition with the coherent one.     

The Coherent-Path Model for Nuclear Resonant Gamma-Ray Scattering: An Overview

Hyperfine Interactions - A “coherent-path” model for nuclear-resonant scattering of gamma radiation from resonant matter has been developed and is summarized here. The solution provides...     

A New Way of Looking at Nuclear Resonant Scattering

A new model for nuclear-resonant scattering of gamma radiation from resonant matter has been developed and is summarized here. This “coherent-path” model has lead to closed-form, finite-sum solutions for radiation scattered in the forward direction. The solution provides a unified microscopic picture of nuclear-resonant scattering processes. The resonant absorber or scatterer is modeled as a one-dimensional chain of “effective” nuclei or “effective” planes. The solution is interpreted as showing that the resonant radiation undergoes sequential scattering from one absorber “nucleus” or “plane” to another before reaching the detector. For recoil-free processes the various “paths” to the detector contribute coherently. The solution for this case gives calculated results that are indistinguishable from those using the classical optical model approach, although the forms of the solutions are completely different. The coherent-path model shows that the “speed-up” and “dynamical beating” effects are primarily a consequence of the fact that the single “effective” nuclear scattering processes are 180° out of phase with the incident radiation while the double nuclear scattering processes are in phase with the incident radiation. All multiple scattering paths are, and must be, included. The model can also treat the incoherent processes, i.e., processes involving gamma emission with recoil or conversion-electron emission. The source of the resonant gamma radiation can be from a radioactive source or from synchrotron radiation: both cases are treated. The model is used to explain and understand the results when each of the following experimental procedures is applied: time-differential Mössbauer spectroscopy, time-differential synchrotron radiation spectroscopy, enhanced-resolution resonant-detector Mössbauer spectroscopy, and the “gamma echo”.     

不同磁场下退火的纳米BiFeO3颗粒的拉曼散射研究

对不同外磁场强度(B = 0T, 5T和10T)下退火的纳米BiFeO3颗粒进行了室温和液氮温度下的拉曼光谱研究。实验发现, 与0T磁场下退火样品的Raman光谱相比, 同一温度下, 纳米BiFeO3颗粒中的Raman振动模式峰的线宽随着磁场的增加而减小, 表明在外磁场的作用下, 纳米BiFeO3颗粒内部的缺陷在减少,晶格完整性得到改善。经外磁场处理的纳米BiFeO3颗粒位于139 cm-1处的A-1模式峰明显向紫端移动, 说明磁有序的程度可以影响到声子-自旋耦合。5T和10T磁场下退火的样品相比, 该峰峰位没有明显改变, 说明影响样品中磁有序排列的磁场存在一个临界值。三块样品的低温拉曼光谱证实了磁场的作用确实影响样品内磁有序的排列。     

Some features of the Resonant Raman Scattering by LO phonons

Resonant Raman Scattering by LO phonons is analysed to obtain a relationship between allowed and forbidden cross sections. The complete expression for the forbidden Raman amplitude induced by the Fröhlich interaction is then used to obtain its dependence on the phonon wave vector with CdS parameters. Comparison with a previous experimental and theoretical work is performed.     

Stability of Complex-Rotation Method on a Simple Resonant Scattering Problem

The stability of the complex-rotation method in B-spline basis for a simple atomic resonant scattering problem in free field is investigated. The numerical calculation shows that this method has a feature that the solution will not change in a wide range of rotation angle θ. Our determined scattering resonant energies and widths exactly coincide with the popularly accepted values. A new resonance is identified numerically although it is very broad. The norm of the complex eigenvalue, ｜E｜, is proposed to investigate and to evaluate the stability of the obtained complex eigenvalues.     

Bremsstrahlung in Resonant Compton Scattering of a Photon by an Atom

Journal of Experimental and Theoretical Physics - An analytic equation for the anomalous magnetic moment of an electron in a static magnetic field in the topologically massive 2D electrodynamics is...     

Branch Processes of Regular Magnetic Monopole

In this paper, by making use of Duan＇s topological current theory, the branch process of regular magnetic monopoles is discussed in detail. Regular magnetic monopoles are found generating or annihilating at the limit point and encountering, splitting, or merging at the bifurcation point and the degenerate point systematically of the vector order parameter field φ（x）. Furthermore, it is also shown that when regular magnetic monopoles split or merge at the degenerate point of field function φ, the total topological charges of the regular magnetic monopoles are stilI unchanged.