Electromagnetic scattering by an arbitrary configuration of dielectric spheres

1990 ◽  
Vol 68 (12) ◽  
pp. 1419-1428 ◽  
Author(s):  
A-K. Hamid ◽  
I. R. Ciric ◽  
M. Hamid
Keyword(s):  
Cross Sections ◽  
Electromagnetic Scattering ◽  
Plane Electromagnetic Wave ◽  
Linear Equations ◽  
Spherical Wave ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Arbitrary Configuration ◽  
Multipole Expansion Method ◽  
Dielectric Spheres

An analytic solution is obtained for the problem of plane electromagnetic-wave scattering by an arbitrary configuration of N dielectric spheres. The multipole expansion method is employed, and the boundary condition is imposed using the translational addition theorem for vector spherical wave functions. A system of simultaneous linear equations is given in matrix form for the scattering coefficients. An approximate solution, which has been developed and employed by the authors for the scattering by N conducting spheres, is extended to the dielectric spheres case. Plots for the normalized backscattering, bistatic, and forward-scattering cross sections are presented over wide ranges of permittivity, size, and electrical separations between the neighbouring spheres. The results show a reduction in the normalized backscattering and bistatic cross sections for certain choices of permittivity relative to conducting arrays of spheres of the same dimensions and separations.

Analytic solutions of the scattering by two multilayered dielectric spheres

1992 ◽  
Vol 70 (9) ◽  
pp. 696-705 ◽  
Author(s):  
A-K. Hamid ◽  
I. R. Ciric ◽  
M. Hamid
Keyword(s):  
Boundary Conditions ◽  
Cross Sections ◽  
Plane Electromagnetic Wave ◽  
Expansion Method ◽  
Analytic Solutions ◽  
Addition Theorem ◽  
Modal Expansion ◽  
Modal Expansion Method ◽  
Dielectric Spheres ◽  
Scattered Fields

The problem of plane electromagnetic wave scattering by two concentrically layered dielectric spheres is investigated analytically using the modal expansion method. Two different solutions to this problem are obtained. In the first solution the boundary conditions are satisfied simultaneously at all spherical interfaces, while in the second solution an iterative approach is used and the boundary conditions are satisfied successively for each iteration. To impose the boundary conditions at the outer surface of the spheres, the translation addition theorem of the spherical vector wave functions is employed to express the scattered fields by one sphere in the coordiante system of the other sphere. Numerical results for the bistatic and back-scattering cross sections are presented graphically for various sphere sizes, layer thicknesses and permittivities, and angles of incidence.

scholarly journals Forbidden transitions in nuclear weak processes relevant to neutrino detection, nucleosynthesis and evolution of stars

2019 ◽  
Vol 223 ◽  
pp. 01063
Author(s):  
Toshio Suzuki ◽  
Satoshi Chiba ◽  
Takashi Yoshida ◽  
Koh Takahashi ◽  
Hideyuki Umeda ◽  
...  
Keyword(s):  
Shell Model ◽  
Cross Sections ◽  
Neutral Current ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Reaction Cross ◽  
Model Calculations ◽  
Multipole Expansion Method ◽  
Supernova Explosions ◽  
Model Hamiltonians

The distribution of the spin-dipole strengths in 16O and neutrino-induced reactions on 16O areinvestigated by shell-model calculations with new shell-model Hamiltonians. Chargedcurrent and neutral-current reactioncross sections are valuated in various particle and γ emission channels as well as the total ones at neutrinoenergies up to Eν≈ 100 MeV. Effects of multiparticle emission channels, especially the αp emission channels, on nucleosynthesis of 11B and 11C in core-collapse supernova explosions are investigated. The MSW neutrino oscillation effects oncharged-current reaction cross sections are investigated for future supernova burst. Electron capture rates for a forbidden transition 20Ne(Og.s.+) → 20F(2g.s.+) in stellar environments are evaluated by the multipole expansion method with the use of shell model Hamiltonians, and compared with those obtained by a prescription that treats the transition as an allowed GamowTeller (GT) transition. Different electron energy dependence of the transition strengths between the two methods is found to lead to sizable differences in the weak rates of the two methods.

scholarly journals On the Convergence of the Multipole Expansion Method

2021 ◽  
Vol 59 (5) ◽  
pp. 2473-2499
Author(s):  
Brian Fitzpatrick ◽  
Enzo De Sena ◽  
Toon van Waterschoot
Keyword(s):  
Expansion Method ◽  
Multipole Expansion ◽  
Multipole Expansion Method

scholarly journals Bonding modes of some labile Si compounds studied by charge density analysis

2014 ◽  
Vol 70 (a1) ◽  
pp. C1698-C1698
Author(s):  
Daisuke Hashizume
Keyword(s):  
Organic Molecules ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Bond Critical Point ◽  
X Ray Diffraction ◽  
Density Distributions ◽  
Density Maps ◽  
Multipole Expansion Method ◽  
Density Analysis ◽  
Electron Donation

Some organic molecules containing Si atom(s) are very labile, even if the corresponding carbon analogs are very stable. To gain information on bonding modes of such compounds, we analyzed valence density distribution, which play critical roles in chemistry of molecule, by applying multipole expansion method. Very recently, an imine coordinated silacyclopropan-1-one, 1, has synthesized by Baceiredo, Kato and co-workers.[1] To clarify the bonding mode of 1, the electron density distributions of 1 and its precursor have analyzed by a multiple expansion method using single crystal X-ray diffraction data. As shown in static model density maps, bonding electrons of Si-C bonds distribute on the outside of the silacyclopropane ring (Si1-C1-C2 ring) (Fig. 1a) with largely extent, in compared with that of the precursor, indicating an in-plane pi-interaction on the Si1-C1 and Si1-C2 bonds. On the other hand, the C1-C2 bonding electrons distribute on the bond, and the bond critical point (BCP) is located on the inside of the three membered ring. In addition, the C1-C2 bonding electrons elongates inside the ring toward the Si1 atom, indicating electron donation from sigma(C1-C2)-bond to the Si1 (Fig. 1b). Consequently, these maps propose greater contribution of canonical structures in Fig. 1c.

scholarly journals Trapped modes around a row of circular cylinders in a channel

1999 ◽  
Vol 386 ◽  
pp. 259-279 ◽  
Author(s):  
T. UTSUNOMIYA ◽  
R. EATOCK TAYLOR
Keyword(s):  
Expansion Method ◽  
Wave Theory ◽  
Multipole Expansion ◽  
Circular Cylinders ◽  
Large Radius ◽  
Trapped Modes ◽  
Resonant Phenomenon ◽  
Trapped Mode ◽  
Linear Water Wave Theory ◽  
Multipole Expansion Method

Trapped modes around a row of bottom-mounted vertical circular cylinders in a channel are examined. The cylinders are identical, and their axes equally spaced in a plane perpendicular to the channel walls. The analysis has been made by employing the multipole expansion method under the assumption of linear water wave theory. At least the same number of trapped modes is shown to exist as the number of cylinders for both Neumann and Dirichlet trapped modes, with the exception that for cylinders having large radius the mode corresponding to the Dirichlet trapped mode for one cylinder will disappear. Close similarities between the Dirichlet trapped modes around a row of cylinders in a channel and the near-resonant phenomenon in the wave diffraction around a long array of cylinders in the open sea are discussed. An analogy with a mass–spring oscillating system is also presented.

X-ray Scattering Studies of Metalloproteins in Solution: a Quantitative Approach for Studying Molecular Conformations, a Quantitative Approach for Studying Molecular Conformations.

1997 ◽  
Vol 30 (5) ◽  
pp. 770-775 ◽  
Author(s):  
J. Günter Grossmann ◽  
S. S. Hasnain
Keyword(s):  
Conformational Changes ◽  
Structural Information ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Quantitative Approach ◽  
Correct Treatment ◽  
Acta Cryst ◽  
Molecular Conformations ◽  
X Ray ◽  
Multipole Expansion Method

The model-independent approach based on the multipole expansion method using spherical harmonics [Stuhrmann (1970a). Acta Cryst. A26, 297–306] has been applied to obtain structural information on a variety of metalloproteins studied by synchrotron X-ray solution scattering. The method is applied to examples (nitrite reductase, transferrin and nitrogenase), not only with the view of comparing protein conformations in solution with those in the crystalline state, but also defining conformational changes and protein-protein interactions which are of functional importance. The shape restoration is found to be straightforward at low resolution (L≤ 3). For correct treatment using higher harmonics, overall molecular symmetry, if present, must be included in the multipole expansion.

Rapid and accurate calculation of small-angle scattering profiles using the golden ratio

2013 ◽  
Vol 46 (4) ◽  
pp. 1171-1177 ◽  
Author(s):  
Max C. Watson ◽  
Joseph E. Curtis
Keyword(s):  
Small Angle ◽  
Golden Ratio ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
Approximation Technique ◽  
Scattering Intensity ◽  
Angle Scattering ◽  
Multipole Expansion Method

Calculating the scattering intensity of anN-atom system is a numerically exhaustingO(N2) task. A simple approximation technique that scales linearly with the number of atoms is presented. Using an exact expression for the scattering intensityI(q) at a given wavevectorq, the rotationally averaged intensityI(q) is computed by evaluatingI(q) in several scattering directions. The orientations of theqvectors are taken from a quasi-uniform spherical grid generated by the golden ratio. Using various biomolecules as examples, this technique is compared with an established multipole expansion method. For a given level of speed, the technique is more accurate than the multipole expansion for anisotropically shaped molecules, while comparable in accuracy for globular shapes. The processing time scales sub-linearly inNwhen the atoms are identical and lie on a lattice. The procedure is easily implemented and should accelerate the analysis of small-angle scattering data.

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