The scattering of slow positrons by CH4 and NH3
The scattering of slow positrons by CH4 and NH3
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CH4 和 NH3 对慢正电子的散射
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
D. Thompson
中科院分区：
文献类型：
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作者：
A. Jain;D. Thompson
采用固定核近似研究了慢正电子与甲烷分子的碰撞。一个静态的潜力和各种模型的极化潜力被用来计算总的弹性截面。最近的实验测量和这些模型的结果之间有相当的一致性。作者还评估了Zeff，即分子的有效湮灭电子数，考虑到由于入射正电子引起的分子轨道畸变的影响。例如，对于CH 4，它们得到99.5，而实验值为140-155。他们认为，没有必要假设正电子-CH 4复合物的形成来解释Zeff的高值。他们还计算了NH3的Zeff，实验值为1300。忽略电荷云畸变的计算得到241。
The fixed-nuclei approximation is used to investigate the collisions between slow positrons and methane molecules. A static potential and various models for the polarisation potential are used to calculate total elastic cross sections. There is fair agreement between recent experimental measurements and the results from these models. The authors also evaluate Zeff, the effective number of annihilation electrons of the molecule, taking into account the effect of distortion in the molecular orbitals due to the incoming positrons. They obtain, e.g. for CH4, 99.5 compared with an experimental value of 140-155. They argue that there is no need to postulate the formation of positron-CH4 complexes to explain the high value of Zeff. They also calculate Zeff for NH3 where the experimental value is 1300. A calculation ignoring charge-cloud distortion gives 241.