Cross section for impact single ionization of B²⁺ by H⁺

The ionization process of B²⁺ by H⁺ impact is studied using the continuum-distorted-wave eikonal-initial-state (CDW-EIS) method and the modified free electron peak approximation (M-FEPA), respectively. Total, single-, and double-differential cross sections from 1s and 2s orbital are presented for the energy range from 10 KeV/u to 10 MeV/u. Comparison between the results from the two methods demonstrates that the total and single-differential cross sections for the high-energy incident projectile case can be well evaluated using the simple M-FEPA model. Moreover, the M-FEPA model reproduces the essential features of the binary-encounter (BE) bump in the double-differential cross sections. Thus, BE ionization mechanism is discussed in detail by adopting the M-FEPA model. In particular, the double- and single-differential cross sections from the 2s orbital show a high-energy hip, which is different from those from the 1s orbital. Based on Ref. 1, the Compton profiles of B²⁺ for 1s and 2s orbitals are given, and the hips in DDCS and SDCS from the 2s orbital are explained.