相对论离子与氦二聚体碰撞电离的理论研究

基于对称程函近似，从理论角度研究了相对论离子与氦二聚体碰撞双电离的直接碎裂通道：由入射离子与两个原子的作用造成的双电离。从不同的近似角度出发，建立了两个理论模型，第一个模型将氦二聚体的两个原子看做一个整体，而另外一个模型完全忽略了两个氦原子之间的相互作用。模型的数值计算结果表明，总截面与氦二聚体的空间取向有很强的依赖关系，当氦二聚体与入射离子束流平行时，总截面达到最大值，在垂直时为最小值。进一步研究发现，模型一的结果在氦二聚体核间距较小时更为合理，核间距较大时，模型二更为精确。

Theoretical Study on the Ionization Process of Relativistic Ion and Helium Dimer Collisions

We study the direct fragmentation channel of double ionization in the collision of relativistic ions and helium dimers from a theoretical point of view. Based on the symmetry eikonal approximation, two theoretical models have been established. In one model, the two atoms of the helium dimer are regarded as a whole system, while the other model completely ignores the interaction between the two helium atoms. The numerical calculation results of the model show that the total cross-section has a strong dependence on the spatial orientation of the helium dimer. When the helium dimer is parallel to the incident ion beam, the total cross section reaches the maximum, and when it is perpendicular, the total cross section reaches the minimum. Further research found that the results of the first model is more reasonable when the helium dimer nucleus distance is small, and the second model is more accurate when the nucleus distance becomes large.