Double ionization of noble gases by positron impact
Double ionization of noble gases by positron impact
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DOI：
10.1103/physreva.60.2940
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发表时间：
1999-10
影响因子：
2.9
通讯作者：
J. Moxom;D. M. Schrader;G. Laricchia;Jun Xu;L. Hulett
中科院分区：
文献类型：
--
作者：
J. Moxom;D. M. Schrader;G. Laricchia;Jun Xu;L. Hulett
给出了从阈值到100 eV的双电离截面和双电离与单电离之比，包括Ne、Ar、Kr和Xe的Ps的形成。在低于第二电离势的6.8 eV能区，即第二能隙内，我们发现Ne有一个无法区分为零的双电离截面，这与以前的测量结果一致。然而，在直接双电离阈值以下的Ar、Kr和Xe的总双电离截面约为每个原子最大双电离截面的7{endash}2 4h{Percent}，其量级均为10{sup{-}2 1}hm{sup 2}，发生在70{endash}90 eV左右。与之前对He和Ne的发现相反，这是第二个矿隙中三种较重的稀有气体发生大量转移电离的直接证据，这与之前对Ar和Xe的测量结果一致。{版权所有}{ital1999}{italthe American Physitive Society}
The cross sections for double ionization and the ratios of double to single ionization, including Ps formation for Ne, Ar, Kr, and Xe are presented from threshold to 100 eV. Within the energy region 6.8 eV below the second ionization potential, i.e., the second Ore gap, we find Ne to have a double-ionization cross section indistinguishable from zero, which is consistent with prior measurements. However, the total double-ionization cross sections for Ar, Kr, and Xe just below the thresholds for direct double ionization are around 7{endash}24h{percent} of the maximum cross-section value for each atom, all of which are of the order of 10{sup {minus}21}hm{sup 2} and occur around 70{endash}90 eV. In contrast to what has previously been found for He and Ne, this is direct evidence of a significant amount of transfer ionization for the three heavier noble gases in the second Ore gap, which is consistent with previous measurements for Ar and Xe. {copyright} {ital 1999} {ital The American Physical Society}