• 제목/요약/키워드: Surface scattering

검색결과 948건 처리시간 0.043초

Wavepacket Correlation Function Approach for Nonadiabatic Reactions: Quasi-Jahn-Teller Model

  • Park, Heesoo;Shin, Changkyun;Shin, Seokmin
    • Bulletin of the Korean Chemical Society
    • /
    • 제35권4호
    • /
    • pp.1061-1066
    • /
    • 2014
  • Time-dependent formulations of the reactive scattering theory based on the wavepacket correlation functions with the M${\phi}$ller wavepackets for the electronically nonadiabatic reactions are presented. The calculations of state-to-state reactive probabilities for the quasi-Jahn-Teller scattering model system were performed. The conical intersection (CI) effects are investigated by comparing the results of the two-surface nonadiabatic calculations and the single surface adiabatic approximation. It was found that the results of the two-surface nonadiabatic calculations show interesting features in the reaction probability due to the conical intersection. Single surface adiabatic calculations with extended Born-Oppenheimer approximation using simple wavepacket phase factor was found to be able to reproduce the CI effect semi-quantitatively, while the single surface calculations with the usual adiabatic approximation cannot describe the scattering process for the Jahn-Teller model correctly.

ZERODUR의 저손실거울의 산란에 대한 연구 (A study on scattering in low loss mirror with superpolished ZERODUR)

  • 이범식;유연석;이재철
    • 한국광학회:학술대회논문집
    • /
    • 한국광학회 2007년도 하계학술발표회 논문집
    • /
    • pp.187-188
    • /
    • 2007
  • Four kinds of mirror substrates with same surface roughness were fabricated. On those substrates, a dielectric multi-layer coating with high reflectivity was deposited by ion beam sputtering technique. Most of the fused silica mirrors showed lower scattering than the ZERODUR mirrors one, which deposited on substrates similar in surface roughness. The ZERODUR mirrors scattering strongly depend on the micro-structure of $Ta_2O_5/SiO_2$ thin films wear deposited on ZERODUR substrates.

  • PDF

임의의 모양을 갖는 회전형 유전체의 전자파 산란 현상 (Electromagnetic Scattering from arbitrarily shaped dielectric Bodies of Revolution)

  • 신용재;김정기
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
    • /
    • pp.18-21
    • /
    • 1987
  • The problem of electromagnetic scattering from arbitrarily shaped lossy dielectric bodies of revolution is studied. Two coupled vector integral equations are formulated from the potential formulas, the equivalence principle and boundary condition. The unknown surface currents (both electric and magnetic) can be found by the moment method, Galerkins's procedure. After the surface currents are determined, the scattering pattern can be evaluated.

  • PDF

Numerical Analysis of Back Scattering from a Target over a Random Rough Surface Using DRTM

  • Yoon, Kwang-Yeol
    • Journal of electromagnetic engineering and science
    • /
    • 제10권2호
    • /
    • pp.61-66
    • /
    • 2010
  • This paper is concerned with an analysis of the back scattering of electromagnetic waves from a target moving along random rough surfaces such as the desert, and sea. First, the discrete ray tracing method(DRTM) is introduced, and then, this method is applied to the back scattering problem in order to investigate the effect of the back scattering from random rough surfaces on the electric field intensities. Finally, numerical examples of various height deviations of the Gaussian type of rough surfaces are shown. It is numerically demonstrated that the back scattering is dominated by the diffractions related to the reflections from the random rough surfaces.

실리콘 웨이퍼 미세 표면결함의 광산란 특성 평가 (Light Scattering Characteristics of Defects on Silicon Wafer Surface)

  • 하태호;송준엽
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2005년도 춘계학술대회 논문집
    • /
    • pp.1083-1086
    • /
    • 2005
  • Light scattering measurement system that can evaluate light scattering characteristic from defects on silicon wafer surface has been developed. The system uses $Ar^+$ laser as an illumination source, and a highly sensitive photomultiplier tube (PMT) for detecting scattered light from defects. Unlike with conventional measurement system, our system has ability to measure scattered light pattern from wide range of scattering angles with changeable incidence condition. It is shown that our developed system is effective to discriminate the types and sizes of defects from basic experimental results using a microscatch and a PSL sphere.

  • PDF

A General Radar Scattering Model for Earth Surfaces

  • Jung, Goo-Jun;Lee, Sung-Hwa;Oh, Yi-Sok
    • 대한원격탐사학회:학술대회논문집
    • /
    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
    • /
    • pp.41-43
    • /
    • 2003
  • A radar scattering model is developed based on an empirical rough surface scattering model, the radiative transfer model (RTM), a numerical simulation algorithm of radar scattering from particles, and experimental data obtained by ground-based scatterometers and SAR systems. At first, the scattering matrices of scattering particles such as a leaf, a branch, and a trunk, have been modeled using the physical optics (PO) model and the numerical full-wave analysis. Then, radar scattering from a group of mixed particles has been modeled using the RTM, which leads to a general scattering model for earth surfaces. Finally, the scattering model has been verified with the experimental data obtained by scatterometers and SAR systems.

  • PDF

숲의 산란계수 계산 모델 개발 (Development of a radar scattering model for forest canopies)

  • 이성화;오이석
    • 한국전자파학회:학술대회논문집
    • /
    • 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
    • /
    • pp.38-42
    • /
    • 2003
  • In this paper, a radar scattering model for forest canopies has been developed based on an empirical rough surface scattering model and the radiative transfer theory. Leaves in the forest canopy are modeled by rectangular resistive sheets, brunches and trunks are modeled by cylinder, which sizes and orientations are randomly distributed. The scattering model has been verified with the measurement data of JPL/AirSAR system.

  • PDF