共查询到20条相似文献,搜索用时 31 毫秒
1.
A.R.W McKellar 《Journal of Molecular Spectroscopy》1983,101(1):186-192
The electric dipole moment of the FO radical () has been directly measured by observing its saturated absorption laser magnetic resonance spectrum (v = 1 ← 0) in the presence of a moderate electric field. The resulting dipole moment [μ(v = 0) = 0.0043(4) D, μ(v = 1) = 0.0267(9) D] is extremely small, and shows a large relative change with vibrational state. The sign of the dipole moment is the same for the two vibrational states. Previous failures to detect microwave or gas phase EPR spectra of FO are fully explained by this small dipole moment. 相似文献
2.
We have studied the physics of atoms with permanent electric dipole moment and nonvanishing magnetic moment interacting with an electric field and inhomogeneous magnetic field. This system can be demonstrated as the atomic analogue of Landau quantization of charged particles in a uniform magnetic field. This Landau-like atomic problem is also studied with space-space noncommutative coordinates. 相似文献
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4.
Strong near-field couplings of anapole modes and formation of higher-order electromagnetic modes in stacked all-dielectric nanodisks
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We theoretically study the near-field couplings of two stacked all-dielectric nanodisks, where each disk has an electric anapole mode consisting of an electric dipole mode and an electric toroidal dipole (ETD) mode. Strong bonding and anti-bonding hybridizations of the ETD modes of the two disks occur. The bonding hybridized ETD can interfere with the dimer's electric dipole mode and induce a new electric anapole mode. The anti-bonding hybridization of the ETD modes can induce a magnetic toroidal dipole (MTD) response in the disk dimer. The MTD and magnetic dipole resonances of the dimer form a magnetic anapole mode. Thus, two dips associated with the hybridized modes appear on the scattering spectrum of the dimer. Furthermore, the MTD mode is also accompanied by an electric toroidal quadrupole mode. The hybridizations of the ETD and the induced higher-order modes can be adjusted by varying the geometries of the disks. The strong anapole mode couplings and the corresponding rich higher-order mode responses in simple all-dielectric nanostructures can provide new opportunities for nanoscale optical manipulations. 相似文献
5.
A new method for extracting the hyperfine anomaly from experimental hyperfine structure constants is suggested. Instead of
independent high-precision measurements of the nuclear magnetic dipole moment, precise measurements of magnetic dipole hyperfine
interaction constants for two atomic states and a theoretical analysis can be used. This can lead to determination of hyperfine
anomaly for radioactive isotopes where the nuclear magnetic dipole moment is not known with high accuracy.
Received: 17 February 1998 相似文献
6.
The Purcell effect is commonly used to increase light emission by enhancing the radiative decay of electric dipole transitions. In this Letter, we demonstrate that the opposite effect, namely, the inhibition of electric dipole transitions, can be used to strongly enhance light emission via magnetic dipole transitions. Specifically, by exploiting the differing symmetries of competitive electric and magnetic dipole transitions in trivalent europium, we demonstrate a fourfold enhancement of the far-field emission from the (5)D(0)→(7)F(1) magnetic dipole transition in trivalent europium. We show that this strong enhancement is well predicted by a three-level model that couples the individual Purcell enhancement factors of competitive transitions from the same excited state. 相似文献
7.
三价铕离子配合物的激光光谱研究 总被引:1,自引:0,他引:1
利用高灵敏度的时间辨激光光谱技术研究了在配位场作用下Eu^3^+的直接激发与发特性。Eu^3^+的直接激发光谱(特别是7F0-5D0的超灵敏跃迁)及其发射光谱随不同的配合物的变化,同时观测到与配位对称性及配位强度有联系的7F1-5D0磁偶极跃 迁的分裂。在对7F0-5D0跃迁共振与非共振的10ps激光脉冲的激励下,都可以立即观察到5D0-7FJ(J=2,3,4)的发射,说明Eu^3^+的5D0能态 相似文献
8.
Salvatore Campione Michael B. Sinclair Filippo Capolino 《Photonics and Nanostructures》2013,11(4):423-435
We review some of the techniques that lead to the effective medium representation of a three-dimensional (3D) periodic metamaterial. We consider a 3D lattice of lead telluride cubic resonators at mid-infrared (MIR) frequencies. Each cubic resonator is modeled with both an electric and a magnetic dipole, through a method called the dual dipole approximation. The electric and magnetic polarizabilities of a cubic resonator are computed via full-wave simulations by mapping the resonator's scattered field under electric/magnetic excitation only to the field radiated by an equivalent electric/magnetic dipole. We then analyze the allowed modes in the lattice, with transverse polarization and complex wavenumber, highlighting the attenuation that each mode experiences after one free space wavelength. We observe the presence of two modes with low attenuation constant, dominant in different frequency ranges, able to propagate inside the lattice: this allows the treatment of the metamaterial as a homogeneous material with effective parameters, evaluated by using various techniques. We then show that the metamaterial under analysis allows for the generation of artificial magnetism (i.e., relative effective permeability different than unity, including negative permeability with low losses) at MIR frequencies. 相似文献
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S. Di Luzio S. Comani G. L. Romani M. Basile C. Del Gratta V. Pizzella 《Il Nuovo Cimento D》1989,11(12):1853-1859
Summary A novel method to investigate the gastro-intestinal activity by means of a superconducting instrumentation based on SQUID
sensors developed for biomagnetic measurements is presented. The magnetic field generated by a small marker ingested by the
subject is measured over the abdomen. The localization of the marker,i.e. a magnetic dipole, is carried out by means of a standard algorithm used in biomagnetic studies. In this way it is possible
to noninvasively study the activity of the gastro-intestinal system. This new approach may lead to important clinical applications. 相似文献
11.
应用基于B样条基组的相对论耦合簇理论方法,计算了~(212)Fr原子的n S (n=7—12), n P (n=7—12)和n D (n=6—11)态的磁偶极超精细结构常数.与精确实验值的比较说明这套理论方法能精确计算出磁偶极超精细结构常数,其中7P态的磁偶极超精细常数的理论值与实验值之间的差异小于1%.在忽略场移效应对Fr原子7P态超精细结构常数的影响下,通过结合实验值进一步定出了~(207-213,220-228)Fr核磁偶极矩μ,这些值与已有的测量值具有非常好的一致性.本文报道了12S, n P (n=9—12)和n D (n=10—11)态的磁偶极超精细结构常数. 相似文献
12.
H. Sharda R.K. Bansal Ashwani Kumar 《The European Physical Journal A - Hadrons and Nuclei》2001,10(3):295-302
Equations illustrating the application of dipole sum rules by relating the reaction strengths from single-particle transfer
(stripping as well as pick up reactions) to the magnetic dipole moment of the target state (derived earlier) have been rewritten
in a more symmetrical and user friendly form. The purpose of the present work is not to calculate the magnetic moment but
to provide six different ways --from stripping and pick up reactions as well as from their combination, to study the discrepancies
in the measurement of reaction strengths through their relationships with the magnetic moment.
Received: 9 November 2000 / Accepted: 16 March 2001 相似文献
13.
Krishanu Nandy Sayani Chaudhuri Ranjan Ganguly Ishwar K. Puri 《Journal of magnetism and magnetic materials》2008
Magnetic microspheres are used as mobile substrates in micro-total-analysis systems (μTAS), since the particles can be selectively functionalized to attach different bioconjugates and can be precisely manipulated using external magnetic field gradients. A large number of MEMS-based bio-analytical devices employ magnetophoretic separation as an important step during their operation. An analytical technique is proposed in this paper that describes the magnetophoretic transport of magnetic microspheres under an imposed magnetic field when there is a pressure-driven or electroosmotic flow through a microchannel. Successful magnetophoretic capture occurs if the strength of the field-inducing magnetic dipole exceeds a critical value, or if the particles are larger than a critical size. The magnetophoretic separator performance is characterized in terms of capture efficiency. The analysis shows that the capture efficiency is a function of two independent non-dimensional parameters, λ and γ that in turn involve all the physical design and operating parameters of the microfluidic separator, e.g., the dipole strength, particle size and susceptibility, fluid viscosity and velocity, channel height, and the separation of the dipole. Parametric plots of capture efficiency as function of λ and γ helps in choosing the right design and operation parameter of a practical microfluidic separator for a target level of performance. 相似文献
14.
We have performed low temperature spin-polarized scanning tunneling microscopy (SP-STM) of two monolayers Fe on W(110) using tungsten tips coated with different magnetic materials. We observe stripe domains with a magnetic period of 50 +/- 5 nm. Employing Cr as a coating material we recorded SP-STM images with an antiferromagnetic probe tip. The advantage of its vanishing dipole field is most apparent in external magnetic fields. This new approach resolves the problem of the disturbing influence of a ferromagnetic tip in the investigation of soft magnetic materials and superparamagnetic particles. 相似文献
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16.
Grandner S Heidenreich S Hess S Klapp SH 《The European physical journal. E, Soft matter》2007,24(4):353-365
The orientational dynamics of rod-like particles with permanent (electric or magnetic) dipole moments in a plane Couette shear
flow is investigated using mesoscopic relaxation equations combined with a generalized Landau free energy. The free energy
contribution due to the coupling between average alignment and dipole orientation is derived on a microscopic basis. Numerical
results of the resulting eight-dimensional dynamical system are presented for the case of longitudinal dipoles and thermodynamic
conditions where the equilibrium state is a (polar or non-polar) nematic. Solution diagrams reveal presence of a large variety
of periodic, transient chaotic, and chaotic dynamic states of the average alignment and dipole moment, respectively, appearing
as a function of Deborah number and tumbling parameter. Compared to rods without dipoles we observe a significant preference
of out-of-plane kayaking-tumbling states and, generally, a higher sensitivity to the initial conditions including bistability.
We also demonstrate that the average (electric) dipole moment characterizing most of the observed states yields electrodynamic
(magnetic) fields of measurable strength. 相似文献
17.
C. Hacker N. Wies J. Gegelia S. Scherer 《The European Physical Journal A - Hadrons and Nuclei》2006,28(1):5-9
The magnetic dipole moment of the Δ(1232) is calculated in the framework of manifestly Lorentz-invariant baryon chiral perturbation
theory in combination with the extended on-mass-shell renormalization scheme. As in the case of the nucleon, at leading order
both isoscalar and isovector anomalous magnetic moments are given in terms of two low-energy constants. In contrast to the
nucleon case, at next-to-leading order the isoscalar anomalous magnetic moment receives a (real) loop contribution. Moreover,
due to the unstable nature of the Δ(1232), at next-to-leading order the isovector anomalous magnetic moment not only receives
a real but also an imaginary loop contribution. 相似文献
18.
YUYAN LIU YUANQING GUO JIELI LIN GUANGMING HUANG CHUANXI DUAN FENGYAN LI 《Molecular physics》2013,111(17):1457-1461
A pair of parallel Stark plates are added to a CO laser magnetic resonance spectrometer to apply electric field in the absorption cell. This apparatus is used to measure the molecular electric dipole moment via Zeeman and Stark effects simultaneously. The saturated absorption spectra of NO (X2Π3/2, ν = 1 ← 0) was observed and the electric dipole moments of NO were directly measured in the presence of an electric field. The dipole moments are determined as μ0(ν = 0) = 0.1595(15) D, μ1 (ν = 1) = 0.1425(16) D. The electric dipole moment of the vibrationally excited state (ν = 1) is determined for the first time. The dependence of the electric dipole moments on its nuclear distances is interpreted. 相似文献
19.
《Physics letters. A》2020,384(27):126696
In this work, we design and numerically demonstrate a touching dielectric nanoantenna with high directionality. This antenna consists of a dielectric cuboid dimer with different heights, and there are no gaps between the subunits of the dimer. Superior unidirectional scattering is achieved when the electric and magnetic dipolar modes inside the antenna satisfy the first Kerker condition. This unidirectional scattering is much more prominent than its components (i.e., the dielectric cuboid nanoantennas with different heights) in the considered spectral region. Furthermore, the radiation angle can be tailored in a 10-degree range by properly rotating the antenna along the out of axis. The off-normal scattering is due to the interference between one induced magnetic dipole and two electric dipoles inside the nanoantenna. Furthermore, we also demonstrate that similar unidirectional scattering effect can also be maintained when the antenna is close to an electric (or magnetic) dipole source, and the forward emission direction can be efficiently controlled by the relative position of the dipole source. Finally, we show that it is possible to further enhance the unidirectionality by arranging the antenna in an array and the main lobe angular beam width of the 2D far-field pattern can be reduced to 28 degree. 相似文献
20.
A. Mason R. Chatterjee L. Fortunato A. Vitturi 《The European Physical Journal A - Hadrons and Nuclei》2009,39(1):107-116
The mirror isobars 7Li and 7Be are investigated in a dicluster model. The magnetic dipole moments and the magnetic dipole response to the continuum are
calculated in this framework. The magnetic contribution is found to be small with respect to electric dipole and quadrupole
excitations even at astrophysical energies, at a variance with the case of the deuteron. Energy-weighted molecular sum rules
are evaluated and a formula for the molecular magnetic dipole sum rule is found which matches the numerical calculations.
Cross-sections for photo-dissociation and radiative capture as well as the S -factor for reactions of astrophysical significance are calculated with good agreement with known experimental data. 相似文献