低能正电子与氦原子的弹性散射

Elastic Scattering of Low-energy Positron by Helium

对电子与氦原子相互作用的模型势进行了修正.用修正前后的模型势计算低能电子被氦原子散射使得S分波相移与实验结果一致,把同样的模型势(忽略交换势)应用到低能正电子被氦原子散射,得到了低能正电子的分波相移、弹性散射截面、动量转移截面.结果表明,用修正后的模型势所得到的结果与实验值符合得很好.从而说明对模型势的修正是合理的.

A new model potential is used for the electron scattering by helium atoms at low incident energies. The potential contains one adjustable parameter to include the effect of short-range correlation. This parameter is determined by fitting calculated cross sections for the elastic scattering of electron by helium atoms with the experimental values of the same. The same value of the parameter is then used for positron-helium scattering at low incident energies. Present results for e^+-He scattering are in good agreement with the experimental values when the energies of incident positrons are under positronium formation threshold.