Distorted Wave Model And Application On Fully Differential Cross Section For Single Ionization Of Helium

In this work,we present fully differential cross section?FDCS?calculations using distorted wave-eikonal initial state?DW-EIS?approximation for helium single ionization by 2 MeV/amu C⁶⁺in the coplanar geometry.Besides,this model also is applied to study the single ionization of helium by 75 keV p impact in the total plane geometry.The transition matrix is introduced using a distorted wave?DW?function and that for the initial state by an eikonal initial state approximation?EIS?which contains the proper asymptotic forms of the projectile-target ion and projectile-electron interactions.Importantly,the final state of ejected electron is treated as a DW calculated purely analytical approximation from the three-Coulomb distorted wave?3C?function.The analytical expression of the transition matrix has been obtained through a series representation of the DW function.Our theoretical results are compared with both experimental measurements and other theoretical calculations.For the 2 MeV/amu C⁶⁺collision,it is shown that the DW-EIS results are reasonably in line with experiment,the magnitudes and the angular distribution of the binary peak is well reproduced.In addition,for the 75 keV p impact,it turns out that the results are in qualitative agreement with the experiment.With increasing momentum transfer,variation of the magnitudes of the peak also is closer to the experimental data.In order to further explore the important role of the distorted wave model in the single ionization,we also discussed the effects of the initial channel interaction potential and the distortion potential in detail.The results show that the FDCS is strongly influenced by the interference effect.We also found that the distorted potential plays a major role in the cross section whereas the contribution of the initial channel interaction potential cannot be ignored.