Positronium scattering by Ne, Ar, Kr and Xe in the frozen target approximation
Positronium scattering by Ne, Ar, Kr and Xe in the frozen target approximation
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冻结目标近似中 Ne、Ar、Kr 和 Xe 的正电子散射
DOI：
10.1088/0953-4075/35/12/303
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
H. Walters
中科院分区：
文献类型：
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作者：
Jennifer E. Blackwood;M. Mcalinden;H. Walters
在冻结靶近似下，发展了正电子素（Ps）与惰性气体散射的全电子耦合态处理方法。采用由9个和22个Ps态组成的耦合赝态展开，计算了Ne和Ar在0-40 eV碰撞能量范围内的Ps（1 s）散射.赝态的目的主要是代表Ps的电离，这被认为是在较高能量下的主要过程。目标激励的First Born估计用于补充冻结的目标结果。详细讨论了现有的实验数据。指出极低能量（≤2 eV）的测量值对应于动量转移截面σmom，而不是弹性截面σel。计算表明，σmom和σel随能量的增加而迅速发散，因此将低能数据与σel进行比较会产生很大的误导。计算结果与σmom的低能测量值以及总截面的高能（≥15 eV）束流测量值之间的一致性不太令人满意。文中还给出了在静态交换近似下Kr和Kr对Ps（1 s）散射的计算结果。
A full-electron coupled-state treatment of positronium (Ps)-inert gas scattering is developed within the context of the frozen target approximation. Calculations are performed for Ps(1s) scattering by Ne and Ar in the impact energy range 0-40 eV using coupled pseudostate expansions consisting of nine and 22 Ps states. The purpose of the pseudostates is primarily to represent ionization of the Ps which is found to be a major process at the higher energies. First Born estimates of target excitation are used to complement the frozen target results. The available experimental data are discussed in detail. It is pointed out that the very low energy measurements (≤2 eV) correspond to the momentum transfer cross section σmom and not to the elastic cross section σel. Calculation shows that σmom and σel diverge very rapidly with increasing energy and consequently comparisons of the low-energy data with σel can be very misleading. Agreement between the calculations and the low-energy measurements of σmom, as well as higher energy (≥15 eV) beam measurements of the total cross section, is less than satisfactory. Results for Ps(1s) scattering by Kr and Xe in the static-exchange approximation are also presented.