• 제목/요약/키워드: Dipole interaction.

검색결과 114건 처리시간 0.018초

Generalization of Keesom Transformation in Multipole-Multipole Interaction Potentials

  • 이천우
    • Bulletin of the Korean Chemical Society
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    • 제16권10호
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    • pp.952-957
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    • 1995
  • In order to ease the treatment of anisotropic potential when developing the variational RRKM theory, we applied Fano-Racah's recoupling theory to the multipole-multipole interaction, resulting in the great simplification of the anisotropic potentials. The treatment appears as a generalization of Keesom transformation in case of dipole-dipole interaction and provides us with great insights to the characteristics of tensorial interactions in the multipole-multipole interaction system.

Cooperative Spontaneous Emission from Nanocrystals to a Surface Plasmon Polariton in a Metallic Nanowire

  • Lee, Joong-Hag;Hong, Suc-Kyoung;Nam, Seog-Woo;Kim, Seog-Seong
    • Journal of the Optical Society of Korea
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    • 제15권4호
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    • pp.407-414
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    • 2011
  • We analyze the cooperative spontaneous emission of optically excited nanocrystals into surface plasmon polaritons propagating on the surface of a cylindrical metallic nanowire. The spontaneous emission probability of the nanocrystals is obtained by perturbative expansions with and without dipole-dipole interaction among nanocrystals in order to see the cooperative effects. The spontaneous emission probability depends on the radial and axial distributions, as well as on the dipolar orientation of nanocrystals. It is shown that the spontaneous emission probability is strongly influenced by dipole-dipole interaction, axial distribution, and dipolar orientation of nanocrystals for closely spaced nanocrystals.

가전기기에서 발생되는 극저주파 과도자계 예측기법 연구 (Study on Prediction Method for ELF Transient Magnetic Field from Home Appliances)

  • 주문노;양광호;명성호;민석원
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제51권11호
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    • pp.616-621
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    • 2002
  • With biological effects by ELF (Extremely Low Frequency) magnetic field generated from power system, the transient magnetic field from electric appliances is a major issue presently. Because the transient magnetic field induces higher current than the power frequency field inside living bodies, transient magnetic field exposure has been much focused. In this paper, it is shown that transient magnetic field from electric home appliances can be characterized as magnetic dipole moment. In this method, the dipole moment vector is assumed by allowing an uncertainty of 6dB in the estimated field. A parameter M that represents biological interaction was applied also. The proposed method was applied to 7 types of appliances (hair drier, heater, VDT, etc.) and their equivalent magnetic dipole moment and harmonic components were estimated. As the results, the useful data for quantifying magnetic field distribution around electric appliances were obtained.

All-optical Polarization Phase Modulation in Coupled Quantum Dots

  • Je, Ku Chul;Kyhm, Kwangseuk
    • Current Optics and Photonics
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    • 제1권1호
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    • pp.60-64
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    • 2017
  • We have considered optical nonlinearities of coupled quantum dots theoretically, where an exciton dipole-dipole interaction is mediated between the adjacent large and small quantum dots. For increasing a pump pulse area in resonance with the large quantum dot exciton the induced nonlinear refractive index of the small quantum dot exciton has been obtained. As the exciton dipole-dipole interaction depends on the relative orientation of two exciton dipoles, the optical nonlinearities for the directions parallel and perpendicular to the coupling axis of the two quantum dots are compared. The directional imbalance of optical nonlinearities in coupled quantum dots can be utilized for a polarization phase modulator by controlling a pump pulse area and propagation length.

Calculation of NMR Chemical Shift for a 3d$^1$ System in a Strong Crystal Field Environment of Tetrahedral Symmetry (1). Application of the Expansion Method for a Spherical Harmonics for Derivation of Overlap and the Dipole Moment Matrix Elements of $\mid$4p > Atomic Orbitals and Derivation of the Radial Integrals for the Hyperfine Interaction for $\mid$4p > Atomic Orbitals

  • Ahn, Sang-Woon;Kim, Dong-Hee;Choi, Chang-Jin
    • Bulletin of the Korean Chemical Society
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    • 제7권4호
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    • pp.299-304
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    • 1986
  • Master formulas for overlap integrals and the dipole moments involving |4p > atomic orbitals have been derived by the expansion method for spherical harmonics. The radial integrals for the hyperfine interaction have also been derived for |4p > atomic orbitals. The calculated values of the overlap integrals and dipole moment matrix elements by the expansion method for spherical harmonics for a hypothetical NO molecule are exactly in agreement with those of Mulliken's method. The radial integrals for the hyperfine interaction may be used to calculate the chemical shift for |4p > atomic orbitals.

Near-field interaction of atoms, molecules and dielectric particles in laser light

  • Minogin, V.G.
    • 한국광학회:학술대회논문집
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    • 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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    • pp.198-198
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    • 2003
  • Two microscopic particles irradiated by light field influence each other by the forces coursed by the dipole-dipole interaction. The interaction changes also the resonance frequencies of the particles. We show that the dipole forces between atoms, molecules or dielectric particles irradiated by laser light play an important role at distances between the particles about or less the light wavelength. We discuss the properties of the near-field forces, including their dependence on direction and polarization of the laser light. We conclude that the near-field forces can be responsible for farmation of dimers in dense atomic gases. The near-field forces can be also used for control the motion of dielectric particles on micro and nanometer scale.

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쌍극자-쌍극자 상호작용 형성을 이용한 향상된 기능의 연료전지용 고분자 전해질 막의 개발 (Development of Polymer Electrolyte Membranes Using Dipole-dipole Interaction for Fuel Cell Applications)

  • 원미희;권소현;김태현
    • 대한화학회지
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    • 제59권5호
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    • pp.413-422
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    • 2015
  • 연료전지는 수소와 산소를 연료로 하여 전기를 생산해 내는 장치로, 전기분해에 의해 음극에서 생성된 수소이온을 양극으로 전달할 수 있는 전해질을 필요로 한다. 전해질로써 Nafion과 같은 불소계 고체 고분자 막이 개발되어 왔으나, 고온에서의 수소이온 전도도 감소 및 높은 함수율에 따른 안정성 감소 등의 문제로 인해 새로운 연료전지용 고분자 전해질 막의 개발을 필요로 하였다. 본 연구에서는 술폰산기가 밀집된 구조를 갖는 단량체를 이용함으로써 높은 수소이온 전도도를 확보하고 이에 따른 고분자 막의 높은 함수율은 고분자 사슬 내에 나이트릴(CN) 작용기를 친수성 올리고머에 함께 도입함으로써 고분자 사슬간 쌍극자-쌍극자 상호작용을 통해 극복할 수 있도록 하였다. 결과적으로 물리적 가교가 형성된 고분자 막들은 높은 함수율 대비 우수한 치수안정성을 나타내었으며, 모든 조성에서 Nafion-117 고분자막에 비해 낮은 IEC값을 가짐에도 불구하고 보다 높은 전도도를 나타내었다.

Estimation of Ground and Excited State Dipole Moments of Coumarin 450 by Solvatochromic Shift Method

  • Naik, L.R.;Math, N.N.
    • Journal of Photoscience
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    • 제12권2호
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    • pp.57-61
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    • 2005
  • The ground and excited state dipole moments of Coumarin 450 (C 450) laser dye were measured at room temperature in several solvents of varying dipole moments. The ground state dipole moment (${\mu}_g$) is estimated by using the modified Onsagar model and the excited state dipole moments (${\mu}_e$) were estimated by the method of solvatochromism as well as by utilizing the microscopic solvent polarity parameter ($E^N_T$). Further, the deviation of some of the points from the linearity of the $E^N_T$ versus Stokes shift indicates the existence of specific type of solute-solvent interaction. The excited state dipole moment of C 450 were found to be higher than those of the ground state and is interpreted in terms of the resonance structure of the molecule. A reasonable agreement has been observed between the values obtained by the method of solvatochromism and modified Onsagar model. It is observed that, corresponding to cyclohexane solution, the fluorescence maxima shift towards the red region with increasing the polarity of the solvents, hence the transition involved are of ${\pi}-{\pi}^*$ type.

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국소장이 원자계에 미치는 영향에 대한 이론 I : 전기 쌍극자계에서의 상호작용 해밀토니안의 유도 (Effect of local field on atomic systems I : Derivation of interaction hamiltonian in electric dipole systems)

  • 안성혁
    • 한국광학회지
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    • 제11권1호
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    • pp.1-5
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    • 2000
  • 전기 쌍극자들로 이루어진 물질계의 총 해밀토니안을 쿨롱게이지내에서 정의하고, 유니타리 변환을 이용하여 쌍극자 근사를 가정할 때 각 쌍극자들에 의한 편극이 궁극적으로 계의 상호작용 해밀토니안에 어떻게 영향을 미치는가를 살펴본다.

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