Low-energy electron-impact ionization of argon: Three-dimensional cross section
Low-energy electron-impact ionization of argon: Three-dimensional cross section
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DOI：
10.1103/physreva.85.032702
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发表时间：
2012-03
影响因子：
2.9
通讯作者：
X. Ren;T. Pflüger;J. Ullrich;O. Zatsarinny;K. Bartschat;D. Madison;A. Dorn
中科院分区：
文献类型：
--
作者：
X. Ren;T. Pflüger;J. Ullrich;O. Zatsarinny;K. Bartschat;D. Madison;A. Dorn
从实验和理论上研究了3$p$电子在Ar中的低能(E}0)电子碰撞单电离。我们的测量是使用所谓的反应显微镜技术进行的，该技术可以覆盖能量低于15 eV的二次电子发射的几乎完整的4个数学{\pi}立体角和从\ensuremath{-}8\ifmmode^\circ\else\textdegree\fi{}到\ensuremath{-}30\ifmmode^\circ\else\textdegree\fi{}.的射束散射角测量的截面在所有散射角和抛射能量范围内归一化。用几种理论模型预测了三重微分截面(TDCS)。它们包括标准的扭曲波Born近似(DWBA)，考虑碰撞后相互作用影响的修正版本(DWBA-PCI)，二阶扭曲波+$R$矩阵的混合方法(DWB2-RM)，以及最近发展起来的带有伪态的$B$-Spline$R$矩阵方法(BSR)。BSR截面的相对角度依赖关系与实验基本一致，在这一低能电子碰撞电离过程中，pCI效应的重要性是显而易见的。然而，计算的TDC和测量的TDC的大小仍然存在显著差异。
Low-energy (${E}_{0}$ $=$ 70.8 eV) electron-impact single ionization of a 3$p$ electron in argon has been studied experimentally and theoretically. Our measurements are performed using the so-called reaction microscope technique, which can cover nearly a full 4\ensuremath{\pi} solid angle for the emission of a secondary electron with energy below 15 eV and projectile scattering angles ranging from \ensuremath{-}8\ifmmode^\circ\else\textdegree\fi{} to \ensuremath{-}30\ifmmode^\circ\else\textdegree\fi{}. The measured cross sections are internormalized across all scattering angles and ejected energies. Several theoretical models were employed to predict the triple-differential cross sections (TDCSs). They include a standard distorted-wave Born approximation (DWBA), a modified version to account for the effects of postcollision interaction (DWBA-PCI), a hybrid second-order distorted-wave plus $R$-matrix (DWB2-RM) method, and the recently developed $B$-spline $R$-matrix with pseudostates (BSR) approach. The relative angular dependence of the BSR cross sections is generally found to be in reasonable agreement with experiment, and the importance of the PCI effect is clearly visible in this low-energy electron-impact ionization process. However, there remain significant differences in the magnitude of the calculated and the measured TDCSs.