• Title/Summary/Keyword: Inelastic scattering

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Resonant inelastic X-ray scattering of tantalum double perovskite structures

  • Oh, Ju Hyun;Kim, Jung Ho;Jeong, Jung Hyun;Chang, Seo Hyoung
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1225-1229
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    • 2018
  • In this paper, we investigated the electronic structures and defect states of $SrLaMgTaO_6$ (SLMTO) double perovskite structures by using resonant inelastic x-ray scattering. Recently, $Eu^{3+}$ doped SLMTO red phosphors have been vigorously investigated due to their higher red emission efficiency compared to commercial white light emitting diodes (W-LED). However, a comprehensive understanding on the electronic structures and defect states of host SLMTO compounds, which are specifically related to the W-LED and photoluminescence (PL), is far from complete. Here, we found that the PL spectra of SLMTO powder compounds sintered at a higher temperature, $1400^{\circ}C$, were weaker in the blue emission regions (at around 400 nm) and became enhanced in near infrared (NIR) regions compared to those sintered at $1200^{\circ}C$. To elucidate the difference of the PL spectra, we performed resonant inelastic x-ray spectroscopy (RIXS) at Ta L-edge. Our RIXS result implies that the microscopic origin of different PL spectra is not relevant to the Ta-related defects and oxygen vacancies.

Low Temperature Magnetization and Spin Wave Excitations in Amorphous Fe67 Co18B14Si1

  • Yoo, Yong-Goo;Yu, Seong-Cho;Hans A. Graf
    • Journal of Magnetics
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    • v.2 no.3
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    • pp.72-75
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    • 1997
  • The temperature dependent saturation magnetization curve of amorphous Fe67 Co18B14Si1, alloy was measured using a SQUID magnetometer and vibrating sample magnetometer from 5 K up to 800 K. Inelastic neutron neutron scattering measurements also have been used to study the long wavelength spin dynamics of this high Tc amorphous ferromagnetic alloy. The magnon dispersion curve exhibit the conventional quadratic relationship E = D (T) q2 + $\Delta$, typical of an iso=obtained from a low temperature magnetization curve, which was consistent with the value obtained from the analysis oif inelastic neutron scattering data after consideration of its temperature dependence.

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Dirac Phenomenological Analyses of 1.047-GeV Proton Inelastic Scatterings from 62Ni and 64Ni

  • Shim, Sugie
    • Journal of the Korean Physical Society
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    • v.73 no.11
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    • pp.1631-1636
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    • 2018
  • Unpolarized 1.047-GeV proton inelastic scatterings from the Ni isotopes $^{62}Ni$ and $^{64}Ni$ are analyzed phenomenologically employing an optical potential model and the first-order collective model in the relativistic Dirac coupled channel formalism. The Dirac equations are reduced to $Schr{\ddot{o}}dinger-like$ second-order differential equations, and the effective central and spin-orbit optical potentials are analyzed by considering the mass-number dependence. The multistep excitation via the $2^+$ state is found to be important for the $4^+$ state excitation in the ground state rotational band for proton inelastic scatterings from the Ni isotopes. The calculated deformation parameters for the $2^+$ and the $4^+$ states of the ground state rotational band and for the first $3^-$ state are found to agree pretty well with those obtained from nonrelativistic calculations.

Memory of Initial States in Scattering over Attractive Potential Energy Surface for Atom-Diatom Collisions

  • Seung-Ho Choi;Hyung-Rae Kim
    • Bulletin of the Korean Chemical Society
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    • v.12 no.4
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    • pp.423-429
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    • 1991
  • Global and local memory functions, defined by Quack and Troe, were calculated for the rotationally inelastic collision of O + SO(v, j)→ [O--S--O]→O + SO(v, j'). It is seen to decrease steadily as total energy increases. Distribution of scattering cross section over product rotational states also shows the decreasing memory of initial state as total energy is increased. These results are interpreted in terms of energy scrambling at high energy due to the availability of more phase space and also the influence of strong dynamical constraints.