Re-examination of a Simplified Model for Positronium-Helium Scattering
Re-examination of a Simplified Model for Positronium-Helium Scattering
复制标题
正电子氦散射简化模型的重新检验
DOI：
10.1088/0953-4075/36/12/302
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
R. J. Drachman
中科院分区：
文献类型：
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作者：
J. DiRienzi;R. J. Drachman
使用局部有效势来解释电子交换，Drachman和Houston(1970年J.Phys.B：在。摩尔。太棒了。1657)在1970年分析了正电子与氦原子的零能散射。这个想法是利用现有的静态交换结果来拟合局部势的参数，然后在变分目标-弹性计算中使用该势。无论是在散射长度还是在湮灭参数方面，结果都是非常好的。然而，最近，Blackwood等人(1999 Phys.教士A604454)强烈反对这些旧的结果，以至于我们重新进行了审查。我们发现，早期工作中的假设，即直接势与交换势相比可以忽略不计，在数量上是不正确的。
Using a local effective potential to account for electron exchange, Drachman and Houston (1970 J. Phys. B: At. Mol. Phys. 3 1657) analysed the zero-energy scattering of ortho-positronium by helium atoms in 1970. The idea was to use the existing static-exchange results to fit the parameters of the local potential and then to use the potential in a variational target-elastic calculation. The results were remarkably good, both for the scattering length and the annihilation parameter. Recently, however, a rigorous target-elastic calculation by Blackwood et al (1999 Phys. Rev. A 60 4454) disagreed so strongly with these old results that we have undertaken a re-examination. We find that the assumption made in the earlier work, that the direct potential is negligible compared with the exchange potential, is not quantitatively correct.