Investigation of quantum states and scattering dynamics of polyatomic molecules by electron and positron impacts

通过电子和正电子撞击研究多原子分子的量子态和散射动力学

• 批准号: 11640397
• 负责人: KIMURA Mineo
• 金额: $ 2.11万
• 依托单位: Yamaguchi University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640397/
• 关键词: Electron and positron impacts; Vibrational excitation; Resonance; Scattering dynamics; Quadrupole interaction; Dipole moment; 共鳴; 散乱断面積; C_6H_6分子; C_6F_6分子; 電子散乱; 陽電子散乱; CF_3I分子; CH_3I分子; 全散乱断面積; CO_2分子; OCS分子

Due to the difference in charge, electrons (e^-) and positrons (e^+) are expected to provide quite different interaction scheme and dynamical mechanisms upon collisions with atoms and molecules. We have investigated vibrational excitation in CO_2 and OCS molecules by (e^-) and e^+ impacts, because both molecules are linear molecules, but OCS molecule has a weak dipole moment while CO_2 has no dipole. We have observed a strong vibrational mode-dependence for vibrational excitation in e^+ and e^- scattering from CO_2 for the first time ; for the symmetric stretching (100) mode, vibrational excitation cross section by e^- scattering is larger by two-three orders of magnitude than that by e^+ scattering, while the cross sections for asymmetric stretching (001) and bending (010) modes are rather similar. Our experimental results are qualitatively consistent to theoretical findings. The weak quadrupole interaction and long-range strong dipole interaction in a combination with the coupling matrix element are responsible to the cause. In addition, the presence of the resonance-like structures was abundantly observed.

由于电荷差，预期电子（E^ - ）和正电子（E^+）将在与原子和分子碰撞时提供完全不同的相互作用方案和动力学机制。我们已经通过（e^ - ）和e^+撞击研究了CO_2和OCS分子中的振动激发，因为两个分子都是线性分子，但是OCS分子的偶极矩较弱，而CO_2则没有偶极子。我们已经观察到第一次从CO_2散射E^+和E^中的振动激发的强振动模式依赖性。对于对称拉伸模式（100）模式，通过E^散射的振动激发横截面比E^+散射的数量级更大，而不对称拉伸（001）和弯曲（010）模式的横截面相当相似。我们的实验结果与理论发现在质性上是一致的。弱的四极相互作用和与耦合矩阵元件组合中的远程强偶极相互作用是原因。另外，观察到了类似共振的结构的存在。

项目成果

M.Kimura, O.Sueoka, A.Hamada, Y.: "ELECTRON AND POSITRON SCATTERING FROM POLYATOMIC MOLECULES"in Adv. Chem. Phys., eds. I. Prigogine and S.A.Rice (John Wiley & Sons, NY,) Vol.111. 537 (2000)

M.Kimura、O.Sueoka、A.Hamada、Y.：“多原子分子的电子和正电子散射”，Adv。

季村峯生, 立川仁典, 平尾公彦: "陽電子と分子の相互作用と衝突過程:陽電子は分子と結合するか?"現代化学(3月号). 16. (2001)

Mineo Kimura、Hitoshi Tachikawa、Kimihiko Hirao：“正电子与分子之间的相互作用和碰撞过程：正电子与分子结合吗？”（2001 年 3 月号）。

M. Kimura: "THEORETICAL CONSIDERATION OF PLASMA PROCESSING GASES., in Adv. At. Mol. Opt. Phys., eds. M. Kimura and Y. Itikawa"Academic Press, NY Vol. 44. 33 (2000)

M. Kimura：“等离子体处理气体的理论考虑。Adv. At. Mol. Opt. Phys.，M. Kimura 和 Y. Itikawa 编辑”Academic Press，纽约卷。

M. Kimura, M. Tachikawa, and K. Hirao: "CAN POSITRON FORM A BOUND STATE WITH MOLECULES?"Modern Chemistry. (in Japanese). (2001)

M. Kimura、M. Tachikawa 和 K. Hirao：“正电子可以与分子形成结合态吗？”现代化学。

R. Suzuki, A. Watanabe, H. Sato, J. P. Gu, G. Hirsch, R. J. Buenkera, M. Kimura, and P. C. Stancil: "CHARGE TRANSFER PROCESSES IN COLLISIONS OF Si^<4+> IONS WITH He ATOMS AT INTERMEDIATE ENERGIES"Phys. Scripta T. 92. 345-347 (2001)

R. Suzuki、A. Watanabe、H. Sato、J. P. Gu、G. Hirsch、R. J. Buenkera、M. Kimura 和 P. C. Stancil：“Si^<4> 离子与 He 原子在中间能量碰撞中的电荷转移过程”